Tag Archives: gems

Regal Greens

4th century gold Tunisian necklace in emerald, sapphire and pearl.

Emerald is May’s traditional birthstone, but since good quality emerald is getting harder to find (I still say the most beautiful ones I ever saw were at the British museum in ancient jewelry) it seemed a good month to look at two other gorgeous green gems.

 

Especially since outside the spring greens are starting to ripen!

 

Chrome diopside

Chrome diopside really needs a trade name. Despite the fact that it sounds like a polishing agent, it is a beautiful green stone that is sometimes used as an emerald replacement.

 

The word diopside comes from Greek, meaning double shape, after the shape of its crystals. Chromium is the element that gives chrome diopside its name and color. Traces of chromium are also what make emeralds green. Oddly enough, it’s also what makes rubies red!

 

Chrome diopside rough

Chrome diopside can indicate proximity to diamond mines. So some people search for minute crystals as a hint of where to mine. Most chrome diopside come from Siberia, near the diamond mines there. It is also sometimes found near the diamond mines of South Africa.

 

It is a much softer stone than emerald. The hardness of stones is measured on the Mohs scale, and chrome diopside sits around 5.5-6.5. That means it is more easily scratched than emerald. It is best used in earrings and pendants; or in rings with a protective setting.

 

Emerald with jardain

Emeralds are tougher. They are rated at 7.5-8 in the Mohs scale; but it is one of the few gemstones expected to have inclusions. Inclusions break up the crystal structure and make both visible and structural flaws.

 

(One of the things I love about emeralds is that even the best gems are expected to have flaws. Visible flaws in emeralds are called jardain, French for garden, for the foliage effect flaws add to the stone.)

 

Green tourmaline showing some of the color variations to wonderful effect. Faceted by Robert Schock.

Tourmaline sits between these two on the Mohs scale at 7-7.5. The name tourmaline covers a large group of related stone species that come in all different colors: clear, yellow, pink, red, brown, green, violet and black. Multicolored crystals are more common than single colored ones.

 

Tourmaline crystal

Originally a lot of the different stones each had their own name; For instance verdelite was the name given to all shades of green and indicolite for all shades of blue tourmaline. Now they’re mostly just referred to as green tourmaline or blue, etc.

 

One of the classic color combinations for tourmaline is the watermelon tourmaline: a crystal that’s green on the outside and shades to pink on the inside, so that the cross-section looks like a slice of melon. (I don’t actually like watermelon, but I’ll take a slice of watermelon tourmaline any time, thank you.)

 

The floral carving is an interesting twist on the watermelon slice tourmaline.

The intense pink and green are normally the most desired tourmaline variants. The pinks range into the most delicious raspberry colors while the best greens can almost put emeralds to shame.

 

Tourmaline is found in many places all over the world. Brazil is the largest supplier, but mines are found on every continent except Antarctica. In the United States tourmaline is found in Maine and California, and is the former’s state stone.

 

I mixed chrome diopside and green tourmaline for an emerald effect in this summer green tree of life pendant.

I mixed chrome diopside and green tourmaline for an emerald effect in this summer green tree of life pendant.

* Care and feeding of chrome diopside- it’s light stable, so it won’t fade in sunlight like some other gems (yes, even natural ones) however, it is sensitive to heat and hydrofluoric acid, so pieces with chrome diopside shouldn’t be cleaned using a steam or ultrasonic cleaner

Leave a comment

Filed under Crafts, Gems

To look at things in bloom

“Loveliest of trees, the cherry now…”

A. E. Housman (1859-1936)

 

Loveliest of trees, the cherry now

Is hung with bloom along the bough,

And stands about the woodland ride

Wearing white for Eastertide.

Now, of my threescore years and ten,

Twenty will not come again,

And take from seventy springs a score,

It only leaves me fifty more.

And since to look at things in bloom

Fifty springs are little room,

About the woodlands I will go

To see the cherry hung with snow.

 

rhodochrosite-tree

I’m cheating a bit, since his cherry blossoms are white. Right now white on trees is a little too much like snow. The cherry I watch every year (a little nervously the past two-the recent winters have left it very bent and twisted) has pink blooms. Light with darker centers, as if they’d been white but stained with cherry juice!

 

I’ve made pink pearl trees to try to get the feel of cherry blossoms, but I haven’t found any small enough to please me. I’m perpetually on the prowl for deep enough rose quartz, but this fall I stumbled on another option for cherry blossom pink stone chips. It’s called rhodochrosite.

 

In its pure form rhodochrosite is nearly rose red. The name comes from the Greek for rose and coloring. Its more common forms are pink and light brown, sometimes grey. Rhodochrosite gets its color from manganese, and the more calcium replacing the manganese the paler it is.

 

Rhodochrosite is fairly soft; it has a Mohs hardness of 3.5-4. That’s one reason it’s rarely faceted, and when it is it’s normally the purer red form for collectors. This does mean that it can be carved into wonderful figures and turned into decorative boxes. I think I first saw the stone with its banding on boxes rather than jewelry. The downside is that it isn’t a good gemstone for rings, and possibly not for bracelets, depending how tough you are on them.

 

It seems to form near silver mines. First it was found in Romania, then later banded stalactites were found in an old Incan silver mine in Argentina. They’d been forming since the mines were abandoned in the 1300s. Argentina is still the principal source of banded rhodochrosite, which is why rhodochrosite is sometimes called rosinca or Inca Rose.

 

The manganese content makes it difficult to refine silver ore so miners used to just dump the rhodochrosite. (*cringe*) Then collectors realized what was being lost!

 

Now it’s Argentina’s national gemstone, and also the state mineral of Colorado.

2 Comments

Filed under Crafts, Gems, Poetry

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 🙂

(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!

1 Comment

Filed under Gems

Chatoyant Skies

Chatoyancy is the term used to refer to the cat’s eye effect that occurs when a fibrous mineral or fibrous inclusions line up parallel to one another and create that famous shimmer. (It comes from the French for cat’s eye.) More generally it can be used to refer to that sort of shimmer and texture, even if it doesn’t create the classic cat’s eye effect.

As chrysocolla reminds me of Claude Monet, blue pietersite is a chatoyant stone that reminds me of El Greco.

Pietersite is breccia aggregate of hawk’s eye and/or tiger’s eye. (It’s chemical makeup is silicon dioxide.)

Those stones are created when silica replaces crocidolite (blue asbestos-sodium iron silicate), a fibrous mineral. Hawk’s eye is when the quartz replaces the crocidolite directly and the rich gold and browns of tiger’s eye occurs when some of the crocidolite has decomposed into iron oxide before the silica replacement happens.

Basically pietersite is hawk or tiger’s eye that’s been broken apart and twisted and generally mangled then squashed back together again. This gives each stone a unique patterning and coloration. Melding swirls, chunks of very different colors all together, a gentle variegation of shades, different angles of chatoyancy in the same color scheme– all in the rich gold and brown and red of iron oxide ranging to sleek grey and steel blues. The one of a kind nature makes for an addictive gemstone-each piece tells its own story.

The pieces with the blue and steel shimmer remind me of El Greco’s moody skies.

El Greco (1541-1614), Domenikos Theotokopoulos, was a Greek-Spanish painter. He was born on the island of Crete (then owned by Venice) studied in Italy, and spent his career in Spain. His time in Crete and Italy appears to have given a slightly Byzantine fascination with color and a feel for mannerist elongated forms.

He moved to Toledo with hopes of becoming a court painter and moving to the capital. He did get two commissions from King Philip, but the king wasn’t satisfied with the paintings and gave him no further commissions. So El Greco settled in Toledo.

His View of Toledo is one of my favorite paintings. The broody ambiance and deceptively simple perspective always intrigues me. Yet there’s something refreshing in the colors. Like a slightly raw breeze after a muggy day.

The Burial of the Count of Orgaz is a beautiful example of the elegance of his elongated figures, his skill at portraiture and shows off how well he handles the complexity of composition.

Sometimes there is a surreal edge to his paintings that makes for an interesting counterpoint to the almost hyperrealism that some of his Spanish Renaissance contemporaries espoused. (Juan Sanchez Cotan and Francisco de Zurbaran are my favorites in that category.)

El Greco’s painting of Laocoon is a great example of his taking the fluid and elongated figures to  nightmarish extremes. (And of a lighter but still tempestuous sky.) It’s inspired by a story from the Aeneid: Laocoon is a Trojan priest who tries to warn his people against taking in the wooden horse that the Greeks left behind. For his pains the vengeful gods send sea serpents to strangle him and his sons and frighten the Trojans into accepting the horse.

3 Comments

Filed under Art, Gems

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 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.

2 Comments

Filed under Art, Crafts, Gems

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

Leave a comment

Filed under Art, Gems, Natural Science

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. (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 Greeks and Romans used them and made fakes out of glass, as did the Egyptians. Cleopatra was said to have emerald mines among her vast wealth. (And there is some evidence that that is truth rather than rumor.) Probably the most beautiful emeralds I’ve ever seen were in 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 gold and silver.

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

The classic emerald cut was designed to reduce the 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…)

3 Comments

Filed under Gems