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’a 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 Dr. Bruce W. Bridenbecker, Treasurer, 7528 Lucerne Vista Ave, Yucca Valley, CA 92284, made out to Friends of Mineralogy.

INSTAGRAM

  • by friendsofmineralogy 2 weeks ago
    Graphite wraps up our  #mineralmonday  trip through the native elements. Like diamond last week, graphite is pure carbon. The difference results from carbon crystallization at much lower pressures and makes diamond and graphite the two naturally occuring allotropes of carbon. Instead of crystallizing in the isometric system like diamond, graphite crystallizes into a honeycomb-like hexagonal sheets. Athough diamonds are of course much harder than graphite, the chemical bonds between carbon atoms in diamonds are actually weaker than those that bond graphite. In graphite, the carbon atoms are tightly bonded into sheets, but the sheets themselves are weakly bonded and can slide easily over each other -- not like the inflexible 3D lattice of a diamond. This makes graphite soft and slick and very useful. Graphite was widely used as a lubricant and coating in the 1500s. It was even key to the success of the English Navy during the reign of Elizabeth I. Fine graphite from Cumbria was used to line the molds for cannonballs, which made the cannonballs smoother so that they could fly farther and straighter. These days graphite is still an used as a lubricant in foundries and steelmaking and is an important component of break linings
  • by friendsofmineralogy 4 weeks ago
    Mineral Identification 101: Part 3. Crystal Morphology (aka crystal shape or habit) Where hardness gave us clues, crystal shape can give us more certainty. Separate mineral species are defined by their chemical composition and their specific crystal structure. While we can't see the structure of the individual molecules, the structure of a mineral is expressed in the external shape of its crystals. So although our three mineral samples are all jumbles of clear crystals on matrix and therefore look superficially similar, close observation will give us the info we need. Last time we used hardness to differentiate the quartz from the calcite and fluorite. Quartz also almost always grows in six-sided prisms topped with a six-sided pyramid, confirming our suspicion from the hardness test. Fluorite and calcite, though-- how to tell apart, if hardness didn't help? A quick glance at a field guide tells us that fluorite has an isometric structure and usually crystallizes as cubes, and that calcite has a trigonal structure with over 800 different identified forms! That's intimidating, but a distraction to our current question, because the most common of those 800 forms are rhombohedrons and scalenohedrons-- definitely NOT cubic. So that's our answer here. The cubic
  • by friendsofmineralogy 3 weeks ago
    Diamond: from the Greek word 'adamas', meaning invincible. Pure carbon in isometric crystals. Although known from antiquity, diamonds were only found in stream or riverbed deposits until the nineteenth century. Diamonds have been mined from these sorts of alluvial deposits in India for more than 3,000 years. Their origin was for a long time rather a mystery; Hindu folklore had it that diamonds were formed by lightning strikes. Following sparse deposits of diamonds up South African streams in the 1860s, more diamonds were found in "yellow earth" above hard diamond-bearing rock called "blue ground", later called kimberlite, after the mining town of Kimberley. The largest of these blue ground locations became the Kimberly Mine in 1871. The area quickly became the center of world diamond production, in only a few years yielding more diamonds than India had in over 2,000 years, although not without greed and obsession and exploitation and blood. This large crystal, approximately 1.5 cm on a size, is from the original Kimberley Mine, which closed in 1914. Kimberlites are an unusual type of volcanic rock that erupted from deep within the mantle and are most often found in the very old areas of continental crust. Not all
  • by friendsofmineralogy 2 months ago
    In 1893, Florence Bascom was the first woman to receive a doctorate from Johns Hopkins University and the second woman in the U.S.A. to recieve a PhD. By that time, she had already earned three bachelor's degrees, a master's degree in geology, and had become a pioneer in the then-new field of petrographic microscopy, even while sometimes being required to sit behind a screen in the the classroom so as to not distract the male students. All of that was just the beginning. By 1894, Florence became the second woman elected a fellow of the Geological Society of America. She was the first woman hired by the USGS (1896) and remained with the USGS well into the 1930s, and ultimately wrote forty articles and seven monographs across her long career. She interspersed summers of field work with microsopic analysis, established innovative methods in teaching crystallography, and completed significant study of Appalacian erosion cycles and mineral resources of the northeast. Florence also taught at Bryn Mawr College beginning in 1895. At that time, geology was considered a part of the natural sciences and was not considered a field of study that would appeal to women. She carved out space for a
  • by friendsofmineralogy 2 months ago
    Although the center of the earth is mostly iron, and iron is one of the most abundant elements in the earth's crust, iron in pure metallic native form is extremely rare at the surface of the earth. Most iron in the earth's crust oxidized into other iron-containing minerals roughly two billion years ago. Ironically (ha) the most common source of metallic iron up here where us humans walk around is not from the earth at all, but has fallen as meteorites! But every once in a great while --much less often than space rocks fall to earth-- pure native iron from within the earth has been found at the surface. This polished chunk of "telluric iron" from Disko Island, Greenland is mixed with blebs of the basalt in which it formed. "Telluric" is after "tellus", the latin name for Earth. The grains and blebs of iron within the basalt are relatively soft and can be hammered into shapes. The Inuit used both telluric and meteorite iron to make sharp knives and cutting edges and were the only people to make practical use of this rare form of iron. Telluric iron is not iron that has been directly dredged up from
  • by friendsofmineralogy 2 weeks ago
    Pliny the Elder, naturalist and Roman military commander in the first century AD, left an incredible legacy in his Natural History, a 37-volume encyclopedia of the collected knowledge of natural history of the time, sourced from personal experience, his own prior works (most of which have been lost), and extracts from other works. Book XXXIII of the Natural History is all about metals and minerals. Pliny was the first to record the correct origin of several earth materials, including as amber as the fossilized tree resin, and made a very early venture into crystallography by describing the octahedral shape of diamond. He was also careful to caution readers about the "considerable difficulty in distinguishing genuine stones from false" and to be wary of fraud by unscrupulous folks who may dye crystal to imitate "smaragdus" (emerald) or other precious stones, or who make sardonyx (banded agate) by gluing together slices of other stones. It is sometimes mentioned that Pliny recommended amethyst as a treatment for drunkenness, but that's not quite right. After noting that this information is one of "the falsehoods of magicians," he states that these sorts of recommendations are "statements which, in my opinion, they cannot have committed to
  • by friendsofmineralogy 3 weeks ago
    Listen up, kids. School is back in session! Today's lesson: The rocks that go into making the average no. 2 pencil. Yeah, you already know that pencil "lead" is actually graphite. But pencils never did contain lead. In the 1500s, most graphite came from Cumbria, England, in blocks that were cut to use as writing implements. Back in those early days of chemistry, graphite was thought to be a form of lead. The term had well stuck by the time it was sorted out. A pencil's ferrule (the metal bit that holds the eraser on) is usually aluminum. Although aluminum is the most common metallic element on earth, it's too reactive with other elements to occur by itself. Bauxite, a sedimentary rock with high concentration of aluminum oxides found in soils of the tropic and subtropic regions, is the primary source of all our aluminum. Bauxite is processed first into aluminum oxide and then into aluminum by electrolysis. Traditional 'pink pearl' type erasers are made of synthetic rubber, stabilized with sulfur, that have a fine pumice added as an abrasive. The pumice is the magic ingredient that makes them actually erase instead of just smudging marks around the paper. These
  • by friendsofmineralogy 1 week ago
    Acanthite! Ever wonder what the dark tarnish is on your silver jewelry? That tarnish is the result of the reaction of silver with sulfur-containing molecules in the air and is silver sulfide: chemically the same as acanthite, the stable form of silver sulfide below 177 °C. The "acanthite" name comes from the Greek word meaning "thorn", which is reminiscent of its crystal shape. The sulfides, which tend to crystallize with a metallic luster and to be more brittle than the native metals, are of great economic importance, because many metal ores are in this group. Some field guides lists argentite, not acanthite, as the primary silver sulfide. These names are sometimes used almost interchangeably, however, because argentite is the stable form of silver sulfide above 177 °C, the only stable form in normal air temperature is acanthite. So, if you see a speciment for sale as "argentite", know it is really an Acanthite pseudomorph after Argentite. Photo credit: Rob Lavinsky & irocks.com 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   #argentite   #acanthite   #geologyrocks   #minerals 
  • by friendsofmineralogy 1 month ago
    Mineral Identification 101: Part 2. Mohs Scale of Hardness Three superficially similar minerals, all three a jumble of clear crystals on matrix: calcite, fluorite, and quartz. Which is which, what to do? Mohs Scale of Harness! Well, it'll help. Completing a hardness test or two usually won't give a definitive answer, not just because the scale is relative, but also because you are unlikely to have precise testing probes at hand. What you probably do have is a penny (scale number 3), a fingernail (scale number 2.5), and a pocketknife (scale number 5-ish). Only the very softest minerals will be scratched by a fingernail, so that's no help here. My penny doesn't have very sharp edges, so that's a wash. OK, that leaves the pocketknife. So, of these three mineral samples, the pocketknife scratches two (look close!). So we know we have one mineral harder than 5, and two softer than five. The harder one must be the quartz, because quartz has hardness of 7. Calcite at 3 and fluorite at 4 are both scratched by the knife. So then-- how to tell which is calcite and which is fluorite? We could try to see which scratches the other, but
  • by friendsofmineralogy 4 weeks ago
    Sulfur. "There are few minerals with which it would be confused," according to Frederick Pough. It's true. In addition to the bright yellow color and several unique diagnostic properties, even well crystallized sulfur pieces like this Sicilian specimen often carry a little whiff of the distinctive rotten-egg odor of hydrogen sulfide, created in the reaction with humidity in the air. Although only a very small amount of hydrogen sulfide is created in this way, the odor is powerful and easily detected by our coarse human noses. Sulfur was called "brimstone" in antiquity, and lives on in that term in the Bible and the association with damnation and divine retribution. Sulfur is still mined in some parts of the world in volcanic areas that belch clouds of sulfurous gases that roar with a hiss, where it is easy to imagine devilish forces beneath, like in this photo of a traditional sulfur mine in Java. Sulfur mines in Sicily were the primary source of sulfur in ancient times. For millenia, conditions at the Sicilian mines were horrific, prompting Booker T. Washington to write in 1912 that "I am not prepared just now to say to what extent I believe in a physical
  • by friendsofmineralogy 1 month ago
    The "Minerals" page from Webster's Home, School and Office Dictionary (1916). A little fine mineral art in a useful leather tome on your parlor room bookshelf. But look close at the "spinel ruby" just left of center. Does this actually show spinel, ruby, or garnets in schist? What say you?  #mineralart   #minerals   #crystals   #mineralcollecting   #mineralogy   #geologyrocks 
  • by friendsofmineralogy 1 month ago
    What is a "Mohs test" and how much does it help? Mineral Identification 101: Part 2 coming tomorrow! Friendly grammar moment: It's a "Mohs test" and not a "Moh's test" because the hardness scale in question was developed by German mineralogist Friedrich Mohs. The more you know!  #minerals   #science   #crystals   #mineralcollecting   #sciencememes 
  • by friendsofmineralogy 2 weeks ago
    We here at Friends of Mineralogy wish you a very happy National Collect Rocks Day! We don't need a special day to appreciate our earth's treasures, but we love an excuse to get out there and add to our collections. How will you be celebrating this fine holiday?  #minerals   #crystals   #geologyrocks   #mineralcollection   #rockcollection 
  • by friendsofmineralogy 2 months ago
    Minerals in the Louvre? This detail from Alexandre-Isidore Leroy De Barde's watercolor painting "Crystallised Minerals" (1814) shows a display of mineral specimens reportedly from renowned English collectors including Jacques-Louis de Bournon (1751-1825), the director of the mineralogy collection of Louis XVIII and namesake to bournonite. Much of de Bournon's collection is now part of the French National Museum of National History. Leroy De Barde was first painter of natural history to Louis XVIII. This painting is one in a series of life-size collection paintings held at the Louvre, the others depicting display collections of preserved birds, seashells, and Etruscan vases, all popular objects held in the "cabinets of curiousity" owned by the rich and powerful of the time. Modern mineral collecting is in many ways an outgrowth of these old cabinets of curiosity. What's in yours?  #minerals   #collection   #mineralcollecting   #history   #art   #mineralart   #crystals 
  • by friendsofmineralogy 1 day ago
    Chalcocite: copper sulfide. Stunning, shining crystals of chalcocite like these from Mammoth Mine, Queensland, Australia are unusual for the species. Much more often, the mineral occurs as massive ore deposits. Chalcocite is an important copper ore known for centuries, and has a variety of historical names to match, including chalcosine, redruthite, vitreous copper and copper-glance. Photo credit: Rob Lavinsky & irocks.com 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   #chalcocite   #copper   #geologyrocks   #minerals   #mineralcollecting   #crystals 
  • by friendsofmineralogy 3 weeks ago
    Need some Sunday reading? New FM Bulletin! Lots of exciting new things are in the works. Link in bio to our website, find it under "Newsletters."
  • by friendsofmineralogy 5 days ago
    September's birthstone is sapphire! One of the most famous sapphires of all is the Star of India, a 563-carat star sapphire. Mined in Sri Lanka and now located at the American Museum of Natural History in New York City, the Star of India is a historic gem that is also a dazzling example of the phenomenon of 'asterism'. Sapphire is a variety of the mineral corundum (aluminium oxide, α-Al2O3). Corundum crystallizes in a hexagonal system, with elongated, six-sided crystals. Star sapphires are included with microscopic inclusions of rutile (titanium dioxide) that are arranged perpendicularly to the rays of six-fold symmetry. A polished cross-section of this crystal can therefore reflect a pattern of a six-sided star, which appears to move and shimmer with slight changes in the angle of reflected light. The Star of India was among several gems commissioned from mineralogist George Kunz by J.P. Morgan in the early years of the 1900s. Kunz wrote in 1913 that the Star of India "has a more or less indefinite historic record of some three centuries," however, details of this historic record are now unknown. The Star of India's fame was increased even higher when it was one of several noted gems
  • by friendsofmineralogy 4 weeks ago
    Crystals have habits? Mineral Identification 101 Part 3 coming tomorrow!  #minerals   #crystals   #mineralogy   #mineralidentification   #science   #sciencememes 
  • by friendsofmineralogy 1 month ago
    Arsenic: "King of Poisons" or "Poison of Kings." Much has previously been written about the long and fascinating criminal and environmental history of this infamous element. Pure native arsenic (number 33 on the periodic table) is not particularly toxic on its own; what most people think of as poisonous 'arsenic' is actually arsenic trioxide “white arsenic,” which is obtained as a byproduct of the processing of ore minerals such as arsenopyrite. Eighteenth century smelters produced massive amounts of white arsenic in many of the same communities that also had large rat populations. Odorless and tasteless white arsenic became a cheap and ubiquitous rat poison. Other forms of arsenic poisons go much farther back in history, back to the time of Nero. The word "arsenic" is related to the Greek word "arsenikos," meaning "masculine" or "potent." At periods, it has been said to be a sexual stimulant, and some men have taken it as an aphrodisiac. Indeed, initial effect of chronic arsenic use can result in improved skin, such as observed by peasants in Austria who found that their complexions and energy improved from the exposure to arsenic from area smelters. Patent medicine inventors of the 1850s took advantage of such
  • by friendsofmineralogy 1 month ago
    Like platinum, tellurium is far more common in the Universe as a whole than on Earth. Tellurium was discovered in the 18th century in a gold ore from the mines in what is now Zlatna, Romania. Tellurium is sometimes found in its native form, but is more often found as the tellurides of gold such as calaverite and krennerite, which are topics for another day. This fine crystallized example (1.8 cm tall) is from Emperor Mine, Vatukoula Gold Field, Viti Levu, Fiji, the source of some of the finest tellurium crystals. Although most Americans don't connect "Fiji" with "mining", gold from Emperor Mine is one of Fiji's largest exports. The mines of Vaukoula ("gold rock" in Fijian) began production under British colonial administration in the 1930s. Fun fact: The town of Telluride, Colorado, was named in hope it would materialize a strike of gold telluride. Alas, only gold and a variety of other precious ores were found, but no tellurides. Photo credit: Rob Lavinsky & irocks.com 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 native elements!