Welcome

The non-profit, Friends of Mineralogy (FM), a national organization founded in 1970, includes nearly a dozen chapters from coast to coast, whose members share a common love of minerals. FM’s objective is to promote, support, protect, and expand the collecting of mineral specimens, while furthering the recognition of the scientific, economic, and aesthetic value of minerals and mineral collecting. Membership includes collectors, museum curators, mineralogists, and earth science educators.  The organization is affiliated with Mindat.org, the Mineralogical Society of America (MSA), and the Mineralogical Association of Canada (MAC).

Among its many activities, FM regional chapters sponsor symposiums, and collecting trips to quarries, mine dumps, and mines across the country.  FM has made its voice heard whenever proposals are made to close mineral museums or collecting sites.  National FM co-sponsors symposiums held annually at the Tucson Gem & Mineral Show, and contributes support and speakers to other mineral symposiums.  FM presents annual awards for best article published in each of the following publications: The Mineralogical RecordRocks & MineralsMineral News, and Mineral Monographs.  It also gives awards to the best institutional and individual educational exhibit cases displayed at the Denver and Tucson gem and mineral shows.


Please send tax-deductible donations to support Friends of Mineralogy, a non-profit 501(c)3 organization, in care of Bruce W. Bridenbecker, Treasurer, 7528 Lucerne Vista Ave, Yucca Valley, CA 92284, made out to Friends of Mineralogy.

INSTAGRAM

  • by friendsofmineralogy 3 months ago
    Mineral knowledge this weekend! August 20, this year’s Dallas Mineral Collecting Symposium will be live-streaming their annual lecture series to a worldwide audience! Innovations in Fine Mineral Recovery at the Eagle’s Nest Mine Daniel Trinchillo Hidden Beauty: Underground Discovery Stories from Arizona and Mexico Les Presmyk San Diego Treasures and the Legendary Bluecap Discovery at the Queen Mine, San Diego Bill Larson Calcite – The Most Collectible Mineral Species Terry Huizing Navajun Pyrite – Perfect Symmetry Thomas Nagin *Prerecorded* Criminal Minerals – Investigating Minerals that Break the Laws Dr. John Jaszczak Crystal Faces and Crystal Forms Dr. John Rakovan Purchase your ticket at dallassymposium.org for $25, with proceeds from our livestream benefitting the Mineralogical Record, Rocks & Minerals, mindat.org, and the Tucson Gem and Mineral Show.
  • by friendsofmineralogy 3 months ago
    Anatase is one of three commonly identified natural polymorphs of titanium dioxide, with rutile and brookite. Polymorphs are mineral species with identical chemical composition but different crystal structure. One polymorph will develop instead of another due to the particular conditions of the environment during formation. Anatase is the most stable of the three polymorphs at low temperatures, but will convert to rutile after the temperature rises above approximately 915oC. Anatase crystals are often sharply attractive, lustrous and opaque or deep blue-tinted translucence, in eight-faced tetragonal dipyramids, as shown in our example. The distinctive elongated crystal shape is why Rene Just Haüy named it after the Greek word for “extension,” anatasis. Synthetic nanoparticles of anatase are used in a wide variety of applications, including photocatalysts. Anatase was used as the titanium dioxide of choice in white paints and pignments known as “titanium white” in the 1920s and 1930s. Unfortunately, it turned out that these whites tended to discolor to a chalky blue-gray under prolonged light exposure. Although both anatase and rutile are photochemically active, rutile was found to be more resistant in these applications, especially when used in combination with additives like zinc oxide. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Main crystal approximately 2.8 cm; from Hardangervidda West, Ullensvang, Vestland, Norway ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #anatase   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 4 months ago
    Maybe you haven’t heard of cassiterite–if that’s so, that changes today! Cassiterite (tin oxide) was one of the most important ores of antiquity and remains the most important ore of tin. As far back as 2,000 BCE, tin was being mined from what is now Cornwall and Devon in Britain. Tin was of essential importance in forging bronze weapons because bronze (copper with 5-20% tin added) is harder than copper alone– all the civilizations of the Mediterranean simply had to have it! In this way, the economy of southwest Britain was brought into the global trade routes at an early date. Trace element and isotopic studies conducted on tin ingots found in shipwrecks off the coast of Turkey and Israel identified the source of this material as the British deposits. These ingots dated back to the 13th century BCE and are hard evidence that cassiterite is one of the minerals that helped create early global trade networks. Cassiterite crystals are fairly hard at 6-7 on the Mohs scale, and because they have a high specific gravity and are more resistant to weathering than surrounding rocks, can concentrate in alluvial (stream) deposits known as placers. Once the ‘easy pickings’ of placer deposits are exhausted, mining may head underground to be found in hydrothermal veins and pegmatites. Today, cassiterite is mined from many places including China, Indonesia, Myanmar, Peru, and Bolivia. Bolivian cassiterites, like the one in our example, are among the most well-formed and collectible. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Cluster approximately 5.4 cm wide; from Viloco Mine (Araca Mine), Loayza Province, La Paz, Bolivia ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #cassiterite  e  #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 4 months ago
    Pyrolusite (manganese dioxide) leaves a mark. Literally. It's usually found in soft, massive deposits that leave fingers smudged. It is much harder (up to Mohs 6.5) when well crystallized like in our image, but these are unusual. Blocks of pyrolusite are commonly found at Neandertal archeological sites, used in making pigment for cave paintings, and possibly also as an aid in firestarting. It's never stopped being useful. It was named from the Greek roots for "to wash" and "fire" in 1827, because it was (and still is) used to help make clear glass by oxidizing iron impurities, which removes the brown and green tints imparted by those iron impurities. It is also used in preparation of chlorine gas and disinfectants as well as a colorant in dyes, paints, and ceramics. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Specimen approximately 6 cm across, from Las Cruces, Doña Ana County, New Mexico, USA. ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #pyrolusite   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 4 months ago
    This sharp and lovely bixbyite-(Mn) is roughly a centimeter across (large for the species!) and is from Thomas Range, Juab County, Utah, the classic USA locality for this mineral. In the 1890s, an amateur mineralogist and dealer named Maynard Bixby was among the first to explore the minerals of the Thomas Range. He found some brightly metallic small cubic crystals of an unknown mineral, which was ultimately named in his honor. After discovery, Bixby kept the precise location of his find a secret for 40 years, probably to keep the information a mystery from potential competitors. Bixbyite in the Thomas Range is found in altered rhyolite rock, sometimes along with other fine small crystals of hematite, red beryl, quartz, and topaz – see the small topaz crystal along the top of the bixbyite in the photo. The crystals tend to be found in small cavities within the volcanic rock that formed as the lava cooled. When we started preparing today’s  #mineralmonday , we had a surprise! Bixbyite isn’t just bixbyite anymore. As of December 2021, the IMA redefined what we had previously learned as bixbyite (iron manganese oxide) into the bixbyite series, because of the very variable ratio of iron to manganese in these crystals and how some specimens contain almost no iron. Species within the bixbyite series can now be classified as Bixbyite-(Mn) and Bixbyite-(Fe) depending on how much iron is contained within the mineral lattice. Science evolves and we'd missed this update. Love to learn! : Rob Lavinsky & irocks.com.  @arkenstone_minerals  ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #bixbyite   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 4 months ago
    Ilmenite (iron titanium oxide) might superficially resemble hematite, but with half of the iron in the crystal lattice replaced by titanium, for centuries it was considered “worthless as an iron ore,” according to Pough. However, when processes to recover the titanium from ilmenite were developed, ilmenite became much more important. Today around half of the titanium dioxide produced worldwide was produced from ilmenite. Titanium dioxide is widely used as a white pigment in paints and coatings, in cosmetics, plastics and paper. Fine, large crystals like the one in our image are relatively unusual for the species. Ilmenite can be mined from hard rock deposits, but most ilmenite is mined from heavy mineral sands deposits, where the heavy minerals have weathered out into concentrated placer deposits. These deposits are additionally attractive because the weathering of the minerals has reduced the iron content and increased the relative percentage of titanium in the deposit. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Crystal with approximate 3 cm crystal faces, from Froland, Aust-Agder, Norway ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #ilmenite   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 5 months ago
    Which is your favorite? Well-formed crystals of hematite (iron oxide) all usually have a dark mirror-like luster, but can vary widely in form and appearance, ranging from flat blades gathered thickly or in rosette shapes, to blocky prisms, to fine small crystals glitter-like “specular hematite”, to rounded bulb or blackberry-like shapes sometimes called “kidney ore.” Hematite is found worldwide. The samples in our image are from famous localities in South Africa, Switzerland, Italy, Brazil, England, and USA. One of the most common minerals on earth, hematite is also the most important ore of iron. Despite the varied crystal forms, all hematite crystals will leave a rusty red color streak behind when abraded. This red color gave hematite the name, derived from the Greek word for blood–and it is the iron in our blood that makes it red. Massive, fine-grained rocks with high concentrations of hematite can also have a similar rusty red color, but “rust” in itself is hydrated iron oxide, not quite the same thing as hematite. More on rust soon! : Collage of worldwide hematite specimens by Erin Delventhal with images from Rob Lavinsky & irocks.com.  @arkenstone_minerals  ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #hematite   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 5 months ago
    Corundum (aluminum oxide) is one of the minerals that helped make our modern world. While the cut gem varieties like ruby and sapphire gather the glory, most corundum is more massive material that is not so visually stunning. Back in the 1890s, you could order corundum grinding wheels through the Sears, Roebuck & Co. catalog for just a few cents each. These "emerendum" wheels used finely powdered emery rock as an abrasive. Emery is a natural rock containing high concentrations of corundum with other minerals like magnetite. Traditional emery nail files use the same stuff! These days, the traditional emery in grinding applications is often replaced by silicon carbide or synthetic corundum, which can be reliably produced from bauxite ore to desired specifications. Corundum still remains a key industrial material thanks to its high specific gravity and extreme hardness (Mohs hardness of 9 to 9.5--almost as hard as diamond). In the 1800s, Swiss watchmakers found that tiny corundum bearings held up well to the constant movement of watch gears. These "jewel movements" helped give Swiss watch brands the positive associations they still hold, even as the natural corundum bearings gave way to synthetic bearings and then digital formats. Synthetic corundum is also an essential part of many lasers, where it is used as the "gain medium" material. The gain medium is the target of an intense burst of light within the laser, causing a brief chain reaction as electrons jump to a higher energy level and emit photons, and in turn strike other atoms in the gain medium and emit more photons. The chain reaction of photons produces the intense light of the a laser. Large sheets of synthetic clear corundum are also used for durable windows in applications like watch faces and grocery scanners. Small, specialized corundum can be used in semiconductors. More massive synthetic corundum is also used for materials like kiln liners and fire bricks.  #oxides   #corundum   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #history   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 5 months ago
    Corundum (aluminum oxide) is more popularly known by its gem varieties: red (containing small amounts of chromium substituting for the aluminum ions) called ruby, and blue (containing trace iron and/or titanium substitutions) traditionally named sapphire. Many of the varietal names are much older than the name “corundum” because of the ancient use of these sturdy and stunning gems. The name “corundum” was only coined in the 18th century. Other gem varieties include padparadscha, which is orange to pink from a mixture of impurities, and star rubies and sapphires, which display “asterism” because of oriented inclusions of microscopic rutile crystals. We also note that these days, gem corundums of all colors (except red) are called sapphire by GIA. For millennia, some corundum gems have been heat-treated to enhance color and clarity. A writer in 1241 CE reported: “In Sarandib [Sri Lanka] and its environs, ruby is treated by fire. People take pebbles from the earth and crush and compress them into a mass with the aid of water. [This mixture] is daubed completely around a dry stone. Then, the whole thing is placed on a rock with other rocks set down around it. Dry firewood is thrown on top, lit and blown upon [with bellows]. The blowing is applied, along with more wood, till any black overtones on the ruby have disappeared. The amount of fire and the application of wood depends on the extent of the blackness present. People know this by experience. They heat-treat stones for at least one hour and, at most, twenty days and nights. Then, they carefully extract the ruby, its blackness having disappeared.” Corundum is nearly as hard as diamond and is industrially useful…more on this on Thursday! : Collage by Erin Delventhal Collage by Erin Delventhal with images from Rob Lavinsky  @arkenstone_minerals  ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #corundum   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcolle 
  • by friendsofmineralogy 5 months ago
    Know what you are lighting up this weekend? All the beautiful bright flaming colors of fireworks are derived from minerals. When fireworks explode, the heat from the explosion causes metal salts to absorb energy from the heat and to emit light of different colors. The color of the light depends on the type of metal or combination of metals present, because the electrons within different metals will excite to different energy states that emit light of a specific energy and that will produce a characteristic color. The heated elements of strontium (usually obtained from celestine, strontium sulfate) produce red light. The addition of sodium salts (from sodium nitrate or sodium chloride) will produce a yellow to orange light. Copper compounds, while producing blue light on their own, will produce lovely purples when mixed with the red of strontium. Green light is from barium (derived from barite, barium sulfate) combined with chlorine. Flashes and bangs and sparks come from aluminum powder or iron filings. Many consumer fireworks are made in China, but the raw materials in American-made fireworks may also come from all over the world. The USA produces quite a bit of copper, but imports most of its strontium from Mexico, barite from China, and sodium nitrate from South America. To assemble a firework, the metals salts and any flashing or spark material are carefully packed, alongside with gunpowder, into an aerial shell in small globs called “stars”. The shell is on a delay fuse, timed carefully to ignite after it is shot into the air from lifting charge. It is the stars exploding that we see as the dazzling bursts of light. These beautiful explosions can reach temperatures of up to 1,800 °F (1,000 °C), as hot as lava! Please remember that much of the American west is still facing significant drought conditions, and to always respect safety of friends and neighbors - please use caution this holiday! : Graphic by Erin Delventhal
  • by friendsofmineralogy 5 months ago
    These golden needles are not hair or straw – they are individual rutile (titanium dioxide) crystals, the longest of which are around one centimeter long. Rutile is more commonly found as more ‘chunky’ darkly opaque to reddish striated prisms; hence why it was named from the Latin rutilus, meaning "red." Rutile is one of the minerals that frequently grows oriented along the crystal faces of other minerals. In this example, the fine rutile needles are oriented along the axes of hematite crystals visible near the bottom of the photograph. This phenomenon, called “epitaxy,” can result in stunningly beautiful starbursts of golden rutile crystals with centers of metallic hematite, embedded within a quartz crystal. Oriented micro growths of rutile crystals are often the cause of ‘star sapphires’ and similar gems. Sands with high concentrations of rutile and other metal ore minerals are known as ‘heavy mineral sands.’ These sands are the result of weathering of igneous and metamorphic rocks with these constituents. Waves and winds have helped to sort the heavy metallic sand grains into higher concentration deposits that can be profitably mined. Rutile sand is then used to manufacture white pigments and refractory ceramics and to produce titanium metal. Rutile is the most common form of several natural titanium dioxides. Others include anatase and brookite…we’ll get there. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Novo Horizonte, Bahia, Brazil ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #rutile   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 5 months ago
    Faden quartz is one of the most unique and distinctive growth forms of quartz, often (but not always) taking the form of flattened prisms linked along a central, wispy line. That wispy line can look like a white thread or string: “faden” (pronounced “fah-den”) is the German word for string. The “faden” is clearly visible in the flattened prism in our example, which is an unusual example of faden quartz because it is still attached to the host rock matrix. Why is it unusual to find Faden quartz crystals still attached to matrix? Because faden quartz forms in rock fissures that widen slowly and steadily. When the fissure opens, small quartz crystals will break on the rupture. Quartz crystal growth is faster along fractured surfaces than regular faces; so in the presence of silica-rich solution the small ruptured crystals will “heal” quickly into new crystal faces. The new crystal will bridge the fissure in the rock. As the fissure widens into a cleft, the crystal continues to grow. Where the initial growth of the faden might be thin, it becomes wider with continued growth and often assumes a platy shape. Repeated slow but continuous rupture and healing leaves a sort of scar inside the crystal in the form of the faden line. The thin line indicates that the widening of the cleft was a mostly continuous movement–if the cleft moved suddenly, the crystals would resume normal growth or develop defined cracks. The faden crystal’s original connection to the rock walls are usually quite delicate and are broken by the time humans find them, and are very difficult to extract if that connection does remain. : Jessica Robertson. Specimen from Tole, Wana, South Waziristan District, Khyber Province, Pakistan.  #quartz   #crystallography   #quartzcrystal   #geologyrocks   #mineralsofig   #earthscience   #mineralcollector   #minerals   #mineralspecimen   #crystaladdict   #crystalsofinstagram   #rocksandminerals   #geologygeek   #earthtreasures   #cabinetofcuriosities 
  • by friendsofmineralogy 5 months ago
    Zincite is the mineral of zinc oxide (ZnO) – the same compound that is the active ingredient in many popular “mineral” sunscreens! Zinc oxide crystals can be grown artificially in a laboratory and as a byproduct of the smelting process, but actual natural crystals of zincite are rare in nature and found in only a few places, like the Franklin Mine in New Jersey, which is also famous for a wide variety of fluorescent minerals. Large and colorful crystals of zincite can sometimes be found on the collector market, often with a story about how they formed in the smokestack of a Polish smelter or refinery that was in need of repair. While it appears that there was an incident in the 1970s where this was true, the majority of zincite crystals currently on the market are intentionally man-made. Natural and synthetic zincite is an important and useful material. Before vacuum tubes were invented, they were used as semiconductor crystal detectors in early crystal radios. As the common white powder of zinc oxide, it was used as paint and ointment at least as far back as the first century BCE. Today it is still used for these purposes, as well as in the rubber and ceramic industries, fire retardants, batteries, as a semiconductor, and much more. Pure zinc oxide is also a common food additive generally recognized as safe by the FDA -- it is the source of zinc in fortified breakfast cereals. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Crystal to 1.4 cm. Franklin Mine, Franklin Mining District, Sussex County, New Jersey, USA ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #zincite   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 6 months ago
    Cuprite is copper(I) oxide (Cu2O) and a minor copper ore. It can form charming cubic and octahedral forms and in red to dark colors ranging from opaque shades to a deep gemmy red. Sometimes called “ruby copper” for the color, it is rarely cut into gemstones because of its softness, 3.5-4 on the Mohs scale. Cuprite is often formed as an oxidation product of copper sulfide minerals, in the upper zones of copper deposit veins. You’ll find it in association with other copper minerals like malachite and chalcocite. The gemmiest red cuprites can be sensitive to light, and can darken into a patina color that could resemble our example (still lovely!). This light-induced decomposition is a transition of the pure cuprite surface into native copper and tenorite. If you are lucky enough to own a gemmy red cuprite crystal, some light protection is advised – storage in a drawer or box for the long term, and low light conditions when on display. : Fabre Minerals  @fabreminerals  4.2 cm. Poteryaevskoe Mine, Rubtsovsky District, Altai Krai Russia ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #cuprite   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 6 months ago
    Do you see a face in this agate? If so, that's pareidolia! Pareidolia is the human tendency to see recognizable patterns where none was intended in inanimate objects-- it's the reason we see animals in clouds, the Man in the Moon, and religious icons in toast or pancakes. "Smiley face" agates are a simple joy caused by our brains' keen ability to translate the banded chalcedony color patterns into facial patterns, and to project emotion into the perceived expression. University of Sydney researcher David Alais told The Gaurdian in July 2021 that “What we found was that actually these pareidolia images are processed by the same mechanism that would normally process emotion in a real face. You are somehow unable to totally turn off that face response and emotion response and see it as an object. It remains simultaneously an object and a face.”  #pareidolia   #science   #agate   #chalcedony   #smile   #minerals   #rocksandminerals   #geologyrocks   #rockhound   #simplejoys 
  • by friendsofmineralogy 6 months ago
    Mineral monday is moving on to the oxides! An oxide mineral is a mineral based on closely packed oxygen atoms (the oxide anion, O2-) that has metal or semimetal atoms in the interstitial spaces. Oxides can be grouped as simple oxides, with one metal, or multiple oxides, with at least two metals. The varied minerals within the oxide class have widely differing physical properties and appearance, but in general tend to be hard and lustrous, and are generally stable under geologic conditions and in the collector’s cabinet. Many oxides are economically significant, and some can be cut into lovely gemstones. Fun fact: Ice (yes, frozen water) and quartz are both technically oxides! They are usually categorized differently due to their unique qualities. ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the oxides!  #oxides   #minerals   #mineralcollecting   #crystals   #geologyrocks   #mineralogy   #science   #chemistry   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 6 months ago
    June is safety month! As more people get outside during the summer months and go look for rocks, it’s a great time for a safety refresher. Put safety to the top of mind while you are planning an excursion, and think about what you are likely to encounter and what makes sense to get you back home in one piece. The mineral collector in our image is on an underground expedition, and has realized she will be on hands and knees in dark spaces – her helmet, knee pads, long sleeves, and heavy boots and gloves will protect head, skin and joints. She is sitting and inspecting finds and has removed the eye protection she might need when doing heavy hammering on rocks. If our mineral collector was instead standing in a quarry, the safety equipment needed might be slightly different – no need for knee pads, for instance. If browsing for agates in an open stream, quite different entirely – no heavy gear, but secure waterproof footwear. The point is to be thoughtful and aware of the situations and environment you are likely to encounter and to be prepared. Preparation doesn’t just mean gear for preventing an injury. It also means having the knowledge for what to do when something does go wrong. Pack a first aid kit and take a first aid course, and know how to get help if needed. If you plan expeditions far from emergency services, consider a wilderness first aid course from an organization like NOLS. And it can not be overstated: beware of ledges above you! A beach bluff or rock ledge may look stable, but can come down in an instant. Come home safe! What are your best safety tips? Photo: Erin Delventhal  #safety   #mining   #rockhound   #community   #minerals   #mineralcollecting   #geology   #crystals   #mineralogy   #geologyrocks   #earthscience   #rocksandminerals   #geologygeek   #earthtreasures 
  • by friendsofmineralogy 6 months ago
    Miargyrite (silver antimony sulfide) is named from the Greek word meyon meaning "smaller" and argyros, meaning "silver." Why “smaller”? It’s not so much that the crystals of miargyrite is really smaller than other silver sulfide minerals (though that is quite often the case), it is more that the silver content is lower than other silver sulfides like pyrargyrite. The example pictured is unusually fine for the species, with a lovely iridescent sheen and ‘rosette’ form. This post finishes up our long  #mineralmonday  romp through the sulfides. There are many more lesser-known sulfide minerals that were not featured in the Pough Field Guide, and perhaps some of those will be subjects for another day. In the meantime, we’re pleased to begin moving on to the next group shortly: the oxides! : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Crystals to 2 cm. San Genaro Mine, Castrovirreyna, Huancavelica, Peru ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the sulfides!  #sulfides   #sulfosalt   #miargyrite   #minerals   #crystals   #geologyrocks   #mineralogy 
  • by friendsofmineralogy 6 months ago
    An 1899 photograph taken at Chicago’s Field Columbian Museum beckons a visitor past the meteorites into the systematic mineralogy gallery. What is “systematic” mineralogy? In the 18th to 19th centuries, at the same time that western naturalists were discovering new-to-them plants and animals and creating detailed taxonomic arrangements of living species into related groups, many scientists were extending these principles of classification to the mineral world. The “system” is a classification of minerals by properties. While you could classify a group of minerals using a wide variety of properties like crystal shape, hardness, etc., the science evolved to determine that classification by chemical composition was the most predictable and useful. James Dwight Dana first published his System of Mineralogy in 1837 with classification based on important chemical groups and structure. Modern classification systems have grown out of Dana’s original system. Today, the International Mineralogical Association (IMA) is the standard body for the definition and nomenclature of mineral species. The IMA currently recognizes 5,780 official mineral species, with more added each year. The generally recognized classes include: native elements, sulfides, sulfosalts, oxides and hydroxides, halides, carbonates, nitrates and borates, sulfates, chromates, molybdates and tungstates, phosphates, arsenates and vanadates, and silicates. Systematic collections were popular among hobbists for many years. Today systematic holdings in museums are important repositories of the science, and there are still many collectors who search out rare species for a systematic collection, but the fashion (and the sheer number of officially recognized species) means that most hobbyist collectors focus their personal collecting framework with different objectives, perhaps focusing on a specific species or region or a certain aesthetic.  #systematicminerals   #mineralcollection   #history   #science   #minerals   #geology   #crystals   #geologyrocks   #mineralogy   #earthscience   #mineralcollector   #rocksandminerals   #geologygeek   #earthtreasures   #cabinetofcuriosities 
  • by friendsofmineralogy 6 months ago
    Jamesonite (lead iron antimony sulfide) can form in masses of hairlike crystals like boulangerite and is sometimes called “feather ore” along with boulangerite and a few related uncommon minerals that are difficult to distinguish, but it can also form in thicker crystals that appear similar to stibnite like the fine example pictured. That’s not for no reason– stibnite is antimony sulfide (Sb2S3), and jamesonite has interconnected SbS3 groups: cousins, of a sort. Jamesonite was named after Robert Jameson, University of Edinburgh professor from 1804 until his death in 1854. Jameson was an influential and prolific mineralogist and geologist and taught many famous scientists of the age, even if his lectures were sometimes considered dry. Charles Darwin (yes, *that* Darwin) reportedly said that Jameson’s lectures inspired him "never to attend to the study of geology." Alas. Seems like it worked out okay for him anyway. : Rob Lavinsky & irocks.com.  @arkenstone_minerals  Crystals to 2.3 cm. Concepción del Oro, Municipio de Concepción del Oro, Zacatecas, Mexico ICYMI: Each  #mineralmonday  we present a mineral species with some history and science, following along the order presented in Frederick Pough's definitive Field Guide to Rocks and Minerals; currently working through the sulfides!  #sulfides   #sulfosalt   #jamesonite   #minerals   #crystals   #geologyrocks   #mineralogy