Wednesday, January 28, 2004

And Now For Something Completely Different

I became interested in minerals after acquiring a pendant made from an amethyst crystal set in silver.  It was so interesting looking that I was motivated to look at it’s mineral roots.  That, of course, expanded into other minerals and resulted in my becoming a collector of sorts.

Today, I’m presenting my desk minerals.  These sit around the desktop computer.  Most of them are quite small, though a few are larger.  I like having them where I can see them most of the time, pick them up, turn them in the light and watch the play of colors.  Yes, I’m nutty about my rocks :)

The top image is a ruby crystal and the bottom image is a sapphire crystal.  They both belong to the corundum family - in fact, they are the only members of that classification.  The red variety is designated as “ruby”.  All other colors (and there are many other colors) are designated as “sapphire”.  Neither of these crystals are gem quality.  You can see in the photos that they are opaque rather than clear.  This means that they have many inclusions (stuff inside the crystal - bubbles, minor crazing, even bits of other materials) that affect the appearance of the stone.  The colors, however, are pretty good and the crystal form is excellent.  The ruby is about .75” long and the sapphire is just about .5”.





Azurite is a carbonate and has a very long and honorable history as a pigment for paints and dyes.  Its intense blue color comes from the presence of copper.  In larger pieces, the blue may be so dark as to make the mineral appear black.  This is quite a small piece and the tiny bladed crystals completely cover the matrix.  Azurite is often found with another mineral called malachite which is a deep, rich green.  Their chemical compositions differ only by a single atom of copper.





Rose quartz is a silicate (as are all the quartzes).  It’s color comes from iron and titanium impurities.  This particular specimen is unusual in that it displays actual crystal growth.  Rose quartz typically manifests as a massif type of growth - it is usually found as big, pink rocks with no particular crystal structure.  This is a tiny piece, just over .5” overall, but the crystal formation is beautiful and the color is perfect.





Citrine is another silicate, another type of quartz.  This crystal is about an inch in length.  A couple of it’s edges are a bit rounded and there are some dings in it that indicate that it may have spent some time tumbling around in a river bed.  Natural citrine is not very common.  In most of the stones on the market, the yellow color has been created by heat treating the much more common amethyst or smoky quartzes.  I feel very fortunate to have this naturally colored crystal - they aren’t available very often.





This is fluorite and it is one of the most colorful species in the mineral kingdom - not that you could tell that from this piece :) Fluorite is a Halide (as is rock salt) and a very common mineral that appears in every color under the sun.  It is not a very hard stone and the above image is not really a crystal.  Though fluorite can grow into octahedral crystals, it usually grows in a cubic form.  The above piece was probably taken from a larger, imperfect specimen that was struck with a hammer.  The octahedral shape falls naturally out of the stone because of fluorite’s cleavage (think of it as grain) - perfect in four directions.  Cut stones are rare because the crystal is so soft, making it very difficult to cut.  This is done once in a while though and the cut stones are brilliant because of fluorite’s wonderful luster.  These stones can only be displayed, however; they are far too fragile for jewelry.

Now for a couple of larger pieces.

This is a chunk of Labradorite and is about 6” long.  This material doesn’t form crystals at all.  It is a feldspar and at first glance, you might think there was nothing special about it at all as its dull grey-to-black surface isn’t particularly appealing or interesting.  But, when you pick it up and turn it in the light, something amazing happens - deep, iridescent colors shimmer out from within the stone in an effect called labradorescence.  This excellent photograph shows a bit if that effect.  The labradorescence may show blue, green, orange or yellow colors and often runs through all of them as the stone is turned in the light.





This is a carved piece of obsidian which has a gold shiller.  Obsidian isn’t a stone at all, but a volcanic glass formed when lava meets water.  The shiller, those concentric, shining rings, are tiny bubbles that were formed in the solidifying process.  Though obsidian is considered a silicate and has the same chemical composition as quartz, it has no crystal structure of it’s own.  And, as a glass, it is fragile.





Manganocalcite gets its beautiful color from manganese.  Unlike most calcites, it is opaque.  This piece is fairly new to me and I am still making its acquaintance, though I have many other, more traditionally transparent/translucent calcite specimens.  Calcite is a carbonate and, like fluorite, can be found in many colors.  Unlike fluorite where colors are intense and saturated, calcite runs to pastels - pink, yellow, orange, green and blue as well as clear.





Finally, (thought we’d never get there, didn’t you :) this bowl holds several small minerals.  The sand in the bowl came from the southern Maine coast.  Starting at the left and proceeding clockwise, the minerals are quartz crystal, hematite, lepidolite, pyrite (fool’s gold), quartz geode, agate and the large piece is red calcite.  There are also a few shells that a friend brought back from her vacation for me.  The contents of the bowl are subject to change from time to time which keeps things interesting :)

One last note - Myria took these photographs for me.  Her eye is better than mine and her camera is much better than mine.  I could never have captured the tiny specimens as well as she did and I give my profound thanks for her time and effort!

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1. Dude! Rocks!

   I love semi-precious stones. Not only that, I love your holders! Snazzy baby!

   Posted by Christina  on  01/28  at  01:30 PM
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2. Thanks Christina :) Like knitting (and, I beginning to suspect, everything else) it’s a mania that leads to stashing!  Except with this one, you get to keep the colors out where you can look at them :)

   Posted by Robbyn  on  01/28  at  02:04 PM
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3. Beautiful pieces! Thanks for showing them off. :) I have several natural crystals, “crystal” balls of various minerals, and a labradorite ring. I swear that thing changes color with my mood. ;) Anyway, it’s always nice to see someone else’s collection...I’m really jealous of the citrine!

   Posted by Bron  on  01/28  at  05:20 PM
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4. A labradorite ring?  How cool!  Any chance you’ll someday post pictures of your shperes?  I’d love to see them :)

   Posted by Robbyn  on  01/28  at  06:59 PM
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5. Hi Robbyn - I’d love to post pics of the spheres (actually, one sphere & one “egg") but that’ll have to wait until I get an updated digital camera. As it is, I’d be posting fuzzy, kinda sparkly blobs! I REALLY need a camera that does close-up work. Sigh.

   Posted by Bron  on  01/29  at  09:25 AM
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