Tag Archives: birthstone

O is for October and Opal

Precious opal is October’s traditional birthstone.


It’s one of my favorite stones, at least to admire if not to work with. Opal is similar to the feldspars in that it has the addictive quality of each gem being different. Boulder opals, trails and pools of opal still in their matrix stone, have a wonderful narrative feel. Like gazing at clouds they have shapes and stories and weather in them.


Opal under a microscope.

Their chemical composition is hydrous silicon dioxide. The stunning colors come from the fact that opal is composed of tiny spheres layered in essentially a silica jelly. The light passing through and refracting off of them is what gives them that fire. How even the spheres and how close together changes the intensity and color.


Opals are between 3% and 30% water. The color can diminish if the opal loses some of its water through heat or cracking. Keeping them in or near slightly moistened cotton wool can prevent drying out over time. Sometimes the play of light in old opals can be partially resuscitated with oil or epoxy resin.


Couldn’t get a decent photo of the ring I’m trying to salvage, so a boulder opal I wrapped with amethyst instead 馃檪

(I’m trying to use oil treatments to save the opal from an old beaten up poison ring. But it was a poison ring, with my birthstone, I had to try it!)


Some attribute the stories about opal being a cursed gem to the fact that special care needs to be taken when working with it. It’s a soft stone, so sensitive to knocks as well as to heat, acids and alkalis.


(I can sympathize with this, I got some Ethiopian opal wet and that was the end of that…I’ve never had trouble with any other sort, but then wire wrapping doesn’t tempt fate too much in terms of either heat or pressure.)


The same is true of wearing them. They’re stunning and not particularly high maintenance, but rings especially are susceptible to being knocked about and dried with or abraded by harsh soaps. So part of the bad luck bad rap may be also be that heirloom quality rings don’t seem to last as long as other gems unless they’re well taken care of over the years!

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A Sparkle from a Moonstone

Sheer blue moonstone.

I love so many different types of stones that choosing a single favorite would be like choosing a favorite dessert-totally impossible. Sometimes you want chocolate, others ice cream, or perhaps it’s fresh fruit you’re craving…

Moonstone is one of my favorites.

It’s a type of feldspar, like labradorite (another favorite of mine). Feldspars are a family of silicates that make up about 60% of the earth’s crust. Large parts of the moon’s crust are composed of feldspars too.

Moonstone聽is one of the traditional birthstones for June, along with alexandrite and pearl.

Moonstone聽has a beautiful shimmer-called adularia-the聽traditional color is blue, and the nearly clear moonstone聽with that ghostly rich blue聽is especially highly valued. There is also grey moonstone and peach-both have a soft white shimmer, and rainbow, which normally is a white or white/clear base with many different colors. The colors come about because the stone’s structure is layered, and those layers refract light at different angles. (Like a built-in聽faceting system!)

A rainbow moonstone piece with peridot.

Moonstone sterling and gold fill pendant

A newer moonstone pendant. They’re tough gems to photograph. The shimmer of this is more on the purple side of blue in most lights. You can also see the spiral from the back through the translucence of the stone.

I like working with rainbow moonstone because of the gorgeous range of colors. The whole rainbow really will appear in some pieces. I also like the fact that each stone will have its own unique pattern of shimmer and color play.

It is a comparatively soft stone. It has a Mohs hardness of 6, which makes it softer than quartz or garnet (though harder than opal) and more easily scratched. I try to avoid the temptation of moonstone rings, since those take the most knocks.

(Title from Cat Steven’s Moonstone.)

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Gems underfoot

I loved Ann Hinde’s display for the International Flower Arranging show’s mineral theme when I saw it this summer. It was inspired by an amethyst geode.

Amethyst is聽a popular stone, one of very few naturally occurring fully purple gems. It is the traditional birthstone for February. Amethyst is a variant of quartz. Iron impurities give it those beautiful shades of purple. Regarding its famous color-if you run across prasiolite, sometimes called green amethyst, just be aware that it’s most likely heat treated or irradiated. (It’s not an issue, so long as you know and aren’t being told or charged for the natural gem. They are a lovely mint green, it’s just that聽the natural stone is extremely rare.)

geode with amethyst pendant

Geodes聽are partially filled hollow cavities in rock that are lined by minerals. Their name comes from the Greek for earthlike. (As in Gaia.)

One example of a geode would be a gas bubble in lava. That hollow stays and over time solutions containing dissolved minerals can filter in and leave deposits within the hollow, often resulting in layers of agate and then layers of聽quartz and/or calcite crystals.

Studying the order of the layers can give a window into the geologic history of the area in which the geode is found.

I like working with slices of geodes because you get to see that external skin and the swirls of agate layers as well as the sparkling crystals.

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Magritte’s Peridot

Peridot Flower ArrangementEarlier this summer I went to the World Association of Flower Arrangers Show. I thought it was a regular flower show, so it was not the photography nirvana that I’d been hoping for. The lighting was abysmal, but there were some really clever category challenges.

My favorite was ‘mineral’. The challenge was based on composing a monochrome composition evocative of a mineral. Not all minerals are monochrome, of course… Some pieces really shone, though plenty skipped the mineral inspiration and stuck to color alone.

There was a great arrangement based on peridot. The clean shape and lines combined with such a perfect green were a nice nod to both August’s birthstone (and perhaps unintentionally) to the Belgian surrealist Rene Magritte.

Son of Man by Rene Magritte

Son of Man by Rene Magritte

Magritte is probably best known for his 1964 portrait, The Son of Man. His paintings are often crisp, with sharp lines and a clear demarcation of color. His idealized yet realistic style underscored the unreliability of images.

The classic example is his Ceci n’est pas une pipe. It’s a painting of a pipe with a line underneath it stating ‘this is not a pipe.’ Which is true, it is an image of a pipe. As the artist himself pointed out, try putting tobacco in it. He revisits this same point in the lesser known Ceci n’est pas une pomme, which came to my mind along with The Son of Man when I saw the peridot arrangement at the show.

Peridot is a pale to middling green gemstone. It’s reasonably durable so suitable for rings. Unlike emeralds, which range from pure to blue tinted green, peridot is normally on the yellow shades of green. (It is also known as olivine for it’s tendency towards olive greens.)

What’s interesting is that it is one of the few gemstones that is almost never treated, so the richness of color you see is truly natural. Also interesting is that peridot has been found in meteorites. I got to see a sample at a gem show last week. They weren’t the most beautiful stones, but it was fascinating to see them growing with the so very foreign metal.

Large stones of the purer green color are unusual and becoming harder to come by. That’s part of the reason I mostly use peridot in my tree of life pendants, stones large enough to wire wrap are few and far between. In chips and cabochons peridot tends to have great dept of color, but it also takes faceting well and聽paler green ones can sparkle brilliantly.

Like most gems that have been known since ancient times, peridot is surrounded by myths and metaphysical attributions. My favorite is that it is supposed to neutralize jealousy and envious thoughts, and so aid in friendships.


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Red Hot July

Ruby by Mucha

Ruby, by Alphonse Mucha

July’s traditional birthstone is ruby. That is the name given to red corundum, all other colors of gem quality corundum are called sapphires. Traces of the element chromium (which in its pure state is a silvery metal!) give the ruby its distinctive shade.

Before 1800 most red gems (like garnets and spinels) were considered rubies. It was only then that ‘ruby’ was recognized to be a different species. (I myself am partial to these spurious ‘rubies’ as garnets are amongst my favorite stones!)

The Black Prince's Ruby

The Black Prince's Ruby, which is actually a spinel.

Rubies are the second hardest gem to diamonds, though they can be quite brittle. The place names often used with rubies tend to be descriptions of color and quality rather than actual location of mining.

When I was little and getting bored at antique shows my mother would have me count all the amethysts. (I’ve always loved purple.) One dealer noticed and my mother explained to her the whole keep me busy thing. The woman was very nice and told me a little about gems. I remember that she was the first to tell me that a good ruby should be really red, maybe with a hint of purple or blue, but not pink. (Though pinkish rubies can be cute, like shimmering gumdrops!) That red is the color I’ve heard referred to a pigeon’s blood. It’s an elemental red, looking, not surpisingly, a lot like fresh blood.

Pigeon's Blood Ruby

Pigeon's Blood Ruby example from GemWise

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Something rich and strange

Full fathom five thy father lies;
Of his bones are coral made;
Those are pearls that were his eyes:
Nothing of him that doth fade
But doth suffer a sea-change
Into something rich and strange.
Sea-nymphs hourly ring his knell

Ariel’s song from The Tempest Act I, scene 2

Creepy, but beautiful images all the same. And the English-geek reason why I love using pearls and fossil coral elements聽together.

I finally found a copy of Rackham’s illustrated Tempest! I found a lead online in the wee hours of the morning and sped out on the hunt the next day. Found a great bookshop, oggled many books, picked up a few. I enjoy the聽old fairytale illustrators a great deal more than I do their contemporary storytellers… Hence the hunt for Shakespeare editions from those eras.

I read The Tempest my senior year in high school after my teacher vetoed every other option I’d put forward.聽(This was after we got into an argument over the meaning of Frankenstein- she insisted that I missed the point and that it was all about Shelley’s anxieties attending motherhood; I thought it was more a fear of science outpacing humanity’s ability to deal with it…)

I remember discussing the play with a woman while we were waiting in line at a book signing. She told me how it was sometimes considered a problem play, since it didn’t fall into the normal divisions of histories, tragedies and comedies. The Tempest is fantasy and romance with elements of tragedy and comedy as well.

It was fun my freshman year in college, because all of my English major friends were having serious issues with the play and I was able to help them. (And lend out my Shakespeare for Dummies book-those scorecards were useful.)

The Tempest is terribly quotable. You can practically trip over references to it. I’ve a print of the painting by Amy Brown called Something Rich and Strange,聽there’s a beautiful comic towards the end of Neil Gaiman’s Sandman using The Tempest as a chance for Shakespeare to look back聽at his life.聽Gaiman also uses it more subtly in his short story Sea Change.

“Those are pearls that were his eyes:” Pearls are one of the birthstones of June, so this聽part of the Tempest聽seemed particularly appropriate.聽Pearls are one of the few organic materials considered to be gems. They’re formed when something gets into a mollusk and it secrets a fluid called nacre to coat the irritant. The traditional example is a grain of sand, but more commonly pearls form around internal damage or parasites sucked in during the mollusk’s feeding. The more (and thinner) layers of slightly translucent nacre, the better the sheen and color of the pearl. Luster and iridescence are created by light breaking up as it goes through or bounces back on the layers of nacre. Most pearls nowadays are cultured, with large irritants being ‘seeded’ into species most likely to produce pearls. So they are yet one more thing that is quite beautiful, but a little creepy upon closer examination…


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An emerald, how beautiful!

May’s traditional birthstone is emerald. It seems like a wonderful option for the northern hemisphere, rich green just as the buds are unfurling into proper leaves.

Emerald is a type of beryl.聽(From aluminum beryllium silicate.) The word itself comes from the Greek for green stone, and probably did originally refer to most green stones. The stone has been known since ancient times, the聽Greeks and Romans used them and聽made fakes out of glass, as did the Egyptians. Cleopatra was聽said to have emerald mines among her vast wealth.聽(And there is some evidence that that is truth rather than rumor.)聽Probably the most beautiful emeralds I’ve ever seen were in聽ancient jewelry in the British Museum. I later years the Spanish plundered large quantities of emeralds from the New World as well as their hauls of聽gold and silver.

The trace elements chrome and vanadium聽both make beryls green, but traditionally only聽beryls colored green through traces of chrome are considered emeralds.聽Gemologists are still debating if a vanadium green beryl is a true emerald. (The authors of my assorted books all disagree with each other聽as well. It sounds like there isn’t an official decision聽if gems are to be classified聽by color or by聽chemistry.)聽Emeralds are one of the few precious stones where inclusions are expected, a too clear gem is considered suspect. Inclusions are euphemistically called聽jardin– french for garden-聽reflecting the shape combined with the color of the stone. (Probably聽my favorite euphemism聽for flaws…)聽Some translucency is a plus, and the deeper greens with a hint of blue are the most valuable.

The classic聽emerald cut was designed to reduce the聽fragile spots on the stone, since they are sensitive to knocks.

A movie moment in honor of emeralds and their fascinating color. Gigi learns about jewelry from her aunt, and to look for that hint of blue that makes an emerald so stunning. (And also a nod to Mother’s Day. The ‘topaz, among my jewels, are you mad’ line is a running joke with my mother…)


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