Category Archives: Minerals

BOOK REVIEW: Orthosilicates

What do you call chemical compounds that are comprised of isolated silica tetrahedron: that is, where the tetrahedrons do not share any corner oxygens with other tetrahedron, but rather are connected by cations in various configurations?  Why, orthosilicates, of course.  Olivine, garnets, zircon, staurolite, and topaz are orthosilicates, to name a few.  So is titanite, one of our favorite Bancroft, Ontario minerals.

When Dr. Robert Lauf arrived at the Rochester Mineralogy Symposium in April he was carting several boxes of his newly minted book entitled “Collector’s Guide to the Silicates: Orthosilicates”.  After his Friday morning talk on the topic, the line to obtain signed copies was predictably long.  I got there early to secure mine, but I do believe Robert was prepared and everyone who desired a signed copy at the symposium was rewarded. Continue reading

The Wollastonite Group of Minerals

Published in the February 2017 WCGMC Newsletter

OK, I know, most of us have heard of the mineral wollastonite and many of us have collected it at the Valentine Mine in Harrisville, or at Rose Road in Pitcairn or Cascade Slide in the Adirondacks. You may even know that 100% of North America’s mined wollastonite comes from two quarries in New York, the aforementioned Valentine Mine and the Lewis Mine near Willsboro.  If you voted in the election of 2013, you may remember Proposition #5 in which the operators of the Lewis Mine sought to trade 1500 acres of their property for 200 acres in Adirondack Park immediately adjacent to the quarries west wall.

But did you know that wollastonite is just one triclinic silicate mineral within what is known as the Wollastonite Group?   These minerals are all single chain silicate minerals in which every third silicate tetrahedral is “twisted”.  Calcium cations connect parallel chains in wollastonite leading the chemical formula CaSiO3.  The lesser known members of this mineral group employ different elements as noted in the accompanying table.

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Larimar

At one of Wayne County Gem and Mineral Club’s  December workshops (and we had two!), Robert Webster arrived with some beautiful larimar to cut, grind and polish.  After his successful work he posted pictures of several of his creations to our club’s Facebook Group page.

Raw, cut larimar (left) and some polished pieces.  All prepped at the WCGMC workshop in December. Specimen and photos by Robert Webster, extracted from his post to the Wayne County Gem and Mineral Club  Facebook group site.

Raw, cut larimar (left) and some polished pieces. All prepped at the WCGMC workshop in December. Specimen and photos by Robert Webster, extracted from his post to the Wayne County Gem and Mineral Club Facebook group site.

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Seavey Road Quarry

Wayne County Gem and Mineral Club’s September Adirondack field trip was another great success.  Seven spots in 4 days with the Saturday AM visit to Benson Mines in Star Lake attracting the most collectors.   33 folks convened and enjoyed a morning collecting in the dumps of the open-pit iron mine just outside town.  Five of the other sites visited were repeats for the club (Rose Road, Benson Mines, Talcville, Valentine Mine, Fine roadcut, and Moose River).  However, we had never been to the Seavey Road marble quarry north of Gouverneur.  Thanks to Ken St. John, who had visited earlier with a small group of fluorescent mineral collectors, and to quarry owner Kevin Dibble, we were able to spend three hours in the large, and very white, quarry.  As a new site for us, the Seavey Road location deserves a review.

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August Birthstone – Peridot

Published in the August WCGMC newsletter

Olivine is one the most common rock-forming silicate minerals on our glorious planet.  It is found in iron and magnesium rich igneous rocks, both extrusive rocks like basalt (think Hawaii) and intrusive equivalents like gabbro and deep mantle rocks called peridotite..  When it is found transparent and unfractured, olivine can be faceted into a brilliant green gemstone.  We call that gemstone peridot and it is the August birthstone.

Olivine Group minerals are nesosilicates, meaning that their mineral lattice consists of isolated silica tetrahedral that are connected by interstitial cations (most commonly iron and magnesium).  This leads to the formula (Mg, Fe)2SiO4.  End member Mg-bearing olivine is the mineral forsterite, while Fe-dominated olivine is the mineral fayalite.  The term chrysolite is sometimes used to label intermediate composition olivine.  Most olivine contains both magnesium and iron, but Mg-rich forsterite is more common than fayalite.

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Trilobites to Tertiary Topaz

Many thanks to Stephen Mayer for writing this collecting trip note for the August WCGMC newsletter and also for allowing me to post it my blog.

By Stephen Mayer

Tammy and I are back from a vacation in the desert southwest.  Naturally, we took some time between visits to National Parks to do a little fossil and mineral collecting in Utah.  The setting and geology are quite different than in western New York.

Very thick shale and calcareous mudstones are widespread in Millard County, west-central Utah and contain some of the best Cambrian biotas in the world.  Not only are there 505-520 million year old fossils abundant, but also recent volcanism in the same region has left its mark with abundant rocks and minerals.  Specifically, well preserved trilobites and beautiful topaz crystals can be collected.

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Pulpit Road Graphite

When I ventured to New Hampshire and Maine with three other intrepid collectors in search of aquamarine, topaz, smoky quartz, and other pegmatite riches, we  did not pass by the planet Mercury (see posting of June 30, 2016).  However, we did find an interesting spot to collect a little graphite.  The site is in extreme eastern New York between the northern end of Lake George and the southern end of Lake Champlain.  Along Pulpit Road, one half mile east of Route 22 in Putnam, NY, a large pile of boulders lay just 50 feet off the roadside.  Bob, Linda, and Gary provide scale to the boulders in the cover photo.

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EMERALD – MAY BIRTHSTONE

It seems we have been here before!  The May gemstone is a repeat of the mineral beryl.  Yes, emeralds are a different color than the March gemstone aquamarine, but mineralogically a beryl is a beryl is a beryl.

The striking green color of an emerald is caused by the introduction of just 0.1-0-5 percent chromium substituting into the aluminum spot of the beryllium silicate mineral.  A small amount of vanadium is also present.  It is truly amazing that just a fraction of a percentage of an element can impart such a striking difference in color.  While the richness and intensity in color is paramount in valuing an emerald, the presence of visible inclusions is also important.  Emeralds lacking inclusions to the eye are considered flawless and carry more value than those with visible inclusions.

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Diamond – April Birthstone

Published in the April WCGMC Newsletter

Diamonds are found in very unusual magmatic intrusive bodies called kimberlites or in alluvial deposits resulting from the weathering and erosion of kimberlites and the concentration of the hard and resistant gems in placer deposits.  Kimberlites are pipe-shaped igneous intrusions that erupted from great depth.  With high gaseous and volatile content, they were able to fracture and penetrate the very thick continental crust, often encapsulating blocks of the fractured host rock as they ascended. (Kirkley et. al.,1991).  Their pipe-like morphology is evident in the picture of the kimberlite pipe quarry from Kimberly, South Africa pictured in the header of this article.

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South African Mineral Maxicards

A Maximum Card (often referred to as a  maxicard) is a  philatelic postcard with a postage stamp placed on the picture side of the card. The stamp and card match or in some way relate to each other.   Maxicards are officially released by many of the world’s postal services, but they are also generated personally by individuals combining a stamp issue with a simple souvenir postcard.   In most cases, the cancellation is also related to the image on the front of the card and the stamp.   

As a collector of minerals, mining and geology on stamps South Africa’s 1984 four-stamp set commemorating some of the country’s strategic resources was a fine add to my collection.  It was not until a couple of years ago, however, that I learned that the officially released Maximum Cards S10-S13 for these stamps featured geologic maps.  Not only would this satisfy another of my topical interests (maps on stamps), but as a retired geologist I found the inclusion of geologic maps on the “Maxicards” most interesting.  Thanks to a tip provided by a fellow member of The CartoPhilatelic Society on the club’s shared discussion site, I was able to purchase a complete set via an online source.

Now it seemed only fitting that I research the stamps and maps a bit.  This note will be constructed to accommodate both Philagems and The New CartoPhilatelist, newsletter of the Maps on Stamps Study Units, as the cards are equally collectible for members of both ATA study units.

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Aquamarine – March birthstone

Written for the March 2016 Wayne County Gem and Mineral Club newsletter

The mineral beryl is hard and can sparkle with exceptional clarity and wondrous color when free of inclusions and defects, clearly justifying its lofty gemstone status.  In fact, not just one gemstone, but several depending on the color imparted by trace amounts of iron, chromium, manganese and other transition elements substituting into the crystal lattice.  Aquamarine, emerald, morganite, and heliodor are all gemstones of the mineral beryl.  But it is sky blue variety that has our special attention this month as aquamarine is the March birthstone.

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The Many Names of Quartz

Published in the February issue of WCGMC News

Quartz is simple.  Right?  Just a silicon (Si) atom nestled in the center of a tetrahedral form surrounded by four oxygen atoms.  Build them together, let the silica-centered tetrahedral motifs share oxygen atoms and bingo we have SiO2.  Quartz crystals grow from this.  They grow into beautiful clear, milky or smoky trigonal crystals with six-sided prisms terminating in six-sided pyramids, simple as a childhood erector set or a Lincoln Log cabin (with that distinctive green roof).  Herkimer diamonds are our favorites, but amethyst and citrine colors are nice too.

OK, but now we are told that quartz which grows rapidly or under “special” conditions can be cryptocrystalline, a condition that exists when the individual quartz crystals are too small to see even with an optical microscope.   And this apparently changes everything.  No longer are we collectors satisfied to apply the common mineral name, albeit with a few modifiers for color (amethyst, citrine, rose quartz).

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Amethyst – February Birthstone

Everyone likes the color purple and mineral collectors like shiny crystal surfaces and perfect terminations.  Therefore, is it any wonder that amethyst attracts attention?   Whether it is spotted in a 2” miniature specimen off matrix, filling a small geode, or covering a huge Brazilian crystal cathedral, eyes are always drawn to the splendor exhibited by a fine amethyst piece.  Given its appeal, is it any surprise that amethyst is the February birthstone?

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Garnet – January Birthstone

Wayne County Gem and Mineral Club has decided to make 2016 the year of the Birthstone.  And isn’t garnet a great way to get started!

garnet 7

Garnets are hard  (Moh’s hardness of 6.5-7.5), or as hard or harder than quartz.  As members of the isometric crystal system garnets are symmetric with three equal and perpendicular axes.  Garnets are colorful: red, yellow, green and many shades of each.  And garnet is the birthstone for all born in January.

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Yellow Mineral Sunshine

Yellow is the color of sunshine, of brilliant warm summer days.  It is the color of bananas, lemon meringue pie and butter pecan ice cream.  There are beautiful yellow breasted birds and wondrous yellow flowers.  Some cultures view yellow as the color of happiness, amusement, and even optimism.

All that is well and good, but yellow is also the color of wulfenite, sulfur, heliodor and a number of other wondrous minerals and gems.  And, of course, it is the color of gold.  It was with this appreciation of the color yellow that WCGMC convened in November for a celebration of “Yellow Minerals”.

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Dravite: A Variety of Tourmaline

This article was published in the November issue of Wayne County Gem and Mineral Club News.  Ninety-one dravites from the WCGMC collection were used to wish the members Happy Halloween.

Dravite is a tourmaline within the Alkali Subgroup 1. This means that the X-site in the complex formula below is predominantly occupied by sodium (Na). In the case of dravite the Y site is occupied by magnesium (Mg) and the Z site is aluminum (Al). The boron cyclosilicate mineral is always dark in color, ranging from chocolate brown to almost jet black. Occasionally, there is sufficient chromium in the Y and/or Z site to impart a dark green color. Dravite is most commonly found in metamorphosed limestones and in higher grade mafic schists.

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Dolomite Gets No Respect

In mid-October, over 130 mineral collectors from several northeast states and Canada converged on Walworth Quarry in upstate New York for the annual fluorite hunt.  Every May, the same crowd treks to Penfield, NY when The Dolomite Group opens that quarry to folks hoping to score a nice transparent-purple fluorite or maybe some dogtooth calcite.  Closer to Buffalo the prized finds are dogtooth calcite, clear selenite, and, of course, small purple fluorites when clubs visit the Lockport Quarry.

Granted the fluorite and other less common vug filling minerals like sphalerite, celestine, and honey colored dogtooth calcite are nice finds and worthy of special attention.  But, there is another fine crystalline mineral hiding in the vugs of the Lockport dolostone.  Yes, I speak of the carbonate mineral, dolomite, or CaMg(CO3)2  Everyone shines their flashlight into the dark vugs of car-sized boulders hoping to see a flat transparent cubic cornered, multi-inch fluorite gleaming back at them.  Absent that observation, collectors move on to the next vug, the next boulder, the next quarry face.

In the next few paragraphs, I am going to try to convince you to take a second look into the vug.  Pause a few seconds to evaluate the white to pink dolomite crystals that you are categorically dismissing as unworthy of your collecting attention.  Are not most of the vugs lined with clean shiny dolomite crystals?  Is there a floater piece in the vug that can be easily removed that displays multiple tiers of brilliantly terminated rhombohedral dolomite?  If yes, just why are these not worthy of extraction?

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