Tag Archives: jewelry

Blue Beyond the Sea

1539-cu-lapis

A piece of lapis with a wire work bail I made to echo its pyrite sparkles.

 

Lapis is sometimes considered a secondary birthstone to sapphire. That’s probably due to its brilliant blue color, and the fact that through the middle ages the word sapphire was used pretty loosely!

 

 

Lapis is a vibrant blue stone consisting of lazurite and usually pyrite and sodalite as well as a host of other minerals. It’s the pyrite that gives lapis its midnight sparkle of stars.

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Fake Pearls, Fashion, and Irritated Bivalves

I don’t generally read romances, but I stumbled on the Two Nerdy Girls blog back when I was researching French costume for a 17th century doll and I love it! They really dig into historical fashions and accessories-the fun fripperies that show us how little people change, but that history books tend to skip.

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Royal Purple

Amethyst from Erte’s Precious Gems Suite

Amethyst is the traditional birthstone for the month of February.

 

(I remember being jealous as a kid, since there were purple stones for February but October always got something pink instead of opal or even fake opal!)

 

Iron impurities in quartz give amethyst its wonderful purples-from pale lilac to royal.

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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

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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.

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Don’t eat the Pomegranate

Garnet is January’s traditional birthstone. I don’t get to work with it as often as I’d like. As a gemstone it’s hard to find large enough to tie into wirework, but I like to use it in beaded accents. I especially love to combine it with pale gems like moonstone and rutilated quartz. Garnet can bring a piece a very modern dramatic feel, or give it a sense of depth and history.

Snow White and Rose Red in silver, bone, enamel and garnet by Eleonore Pieper

 

After all, it’s a gemstone with a long history.

 

4th century Hunnish fibula (pin) in gold and garnet

 

By the bronze age people were using it both in jewelry and as an abrasive. It’s been found in ancient Egyptian, Greek and Roman jewelry. In ancient times garnets were carried by explorers as talismans against the dangers of the dark.

 

 

The name garnet comes from the Latin word for grain, probably because the red crystals reminded people of pomegranate seeds.

 

Striking garnet pomegranate by Natalia Moroz of WingedLion

 

In Anglo-Saxon times square garnets set in gold for a cloisonné effect were inspired by garnet and enamel pieces all the way from Byzantium!

 

Anglo-Saxon hilt fitting

Garnet is the name for a group of different types of stones with similar chemical forms but different chemical compositions.

 

Different chemicals=different colors, not all garnets are red! These are called different species of garnet.

 

Some of the garnet spectrum…

 

Since they have different chemical compositions they also have different hardnesses. Most are hard enough for everyday wear, even on rings.

 

The three species you’re most likely to come across are:

 

-Almandine-one of the hardest. The good quality dark wine red is used for gems and the lesser as grit for drills and sandpaper. This is probably the one that pops to mind when someone says garnet.

 

Burning coal, wire wrap of a garnet crystal in schist.

Burning coal, wire wrap of a garnet crystal in schist.

 

For those of you who like reading historical novels, almandine is what was once called carbuncle. That word has roots in the Latin for live coal-you can see crystals of garnet embedded in metamorphic rocks.

 

-Pyrope-(from the Greek for fire-eyed-is it bad that I think that would be a great name?) is mostly red in color, crimson with a hint of orange.

 

My favorite version of this species is called rhodolite garnet. (Found in North Carolina and East Africa, go figure.) It’s a chemical mix between pyrope and almandine and somehow looks like neither. It has a wonderful purplish pink cast. Rhodolite is almost always cut into gemstones and rarely made into beads or chips.

 

Rhodolite garnet

 

-Grossularite-garnets are often really pretty, despite the terrible sounding name! (Apparently it derives from a name for gooseberry, what the crystal clusters are supposed to resemble!)

 

One variation of this is tsavorite garnet, which is an amazingly beautiful green created by traces of chromium. It’s only been known since the seventies and is still working its way into the market, but it’s gotten much more popular in the last decade or so. (Perhaps as good quality emeralds are getting harder to come by?)  If green were a primary color, it’d be tsavorite. Sadly the crystals are normally found shattered, so large stones are rare.

 

Tsavorite garnet

 

Garnets practically run the spectrum. They’re a little short on blue, but there are rare blue-green ones that change to purple under incandescent light!

 

(*Note on the care and feeding of garnets: soap and water are your best options. Most almandine and pyrope and pretty stable, but some species can be hurt by sonic or steam cleaning.)

A chart with further species and varieties of garnet

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Jurassic Reliquary

 

This is a piece of agazitzed dinosaur bone inlaid with ammolite that I wrapped in 14K gold fill. I couldn't resist this striking combination of fossils.

This is a piece of agazitzed dinosaur bone inlaid with ammolite that I wrapped in 14K gold fill. I couldn’t resist this striking combination of fossils.

Agatized dinosaur bone is sort of like meteorite, it’s awesome just BECAUSE.

 

If you look at a cross section of a bone you’ll see holes. These are the places that used to house blood vessels and bone marrow.

 

Gem bone dealers call these spaces cells. And they are, in the sense of small enclosed places. What they are not is cells in the biological definition that involves nuclear material surrounded by a membrane or wall. Here we’re talking about seeing the larger structures formed by the bone cells.

 

Agatized dinosaur bone is the result of these empty places being replaced with mineral materials. The most common of these is chalcedony. Transparent chalcedony with patterns or banding is called agate, so dinosaur bones replaced with chalcedony are called agatized dinosaur bone, dino bone, or gem bone.

 

The largest gem bone deposits are in Utah and Colorado from the late Jurassic Morrison Formation. It is around 200-150 million years old and formed from silt and sand from flood plains.

 

There are a lot of variables to evaluating gem bone! There’s also a lot of division between what specimen collectors and jewelers will be looking for.

 

-Color. The brighter the better. Neutral colors are less in demand for collectors, though they work well for jewelers. Black is the most desirable for the cell outlines, followed by white, since both will give a dramatic contrast.

 

-Intensity. Again, the most intense, rich colors are generally the most in demand. Pastel colors are rare, so some prefer them. (I myself really like the hard to find delicate baby blue color.)

 

-Number of Colors. Apparently seven colors in one fossil is the least found and the most prized. I’ve never seen one like that in real life.

 

-Durability. Chalcedony is a fairly hard stone. Some of the other minerals found in gem bone-opal and calcite-are much softer, but calcite is supposed to improve the brightness of color and give the surface of the stone a silvery sheen. So again it depends on what it’ll be used for-a display piece needs less durability than a ring inlay.

 

-Cell Size. Generally the larger the better, so long as the contrast is good.

 

-Cell Pattern. There is a very rare fanning pattern only found in the vertebrae of some species, it’s generally a collectors only item since it’s considered too rare to cut up for jewelry.

 

-Type of Bone. For collectors the vertebrae with their unusual patterns, especially if they’re part of a pair. The ends of large bones are valued by both collectors and jewelers because they’re more likely to have large and well defined cells.

 

-Completeness of Bone. Again, for collectors. Complete bones are more valuable.

 

 

This would be a really awesome fortification with amethyst crystals. From the Smithsonian.

-Presence of Agate Fortifications. They sound to me like particularly beautiful castles, but apparently this is the proper term for the little crystal surprises you sometimes find in the bone. Sometimes fractures or large cells are filled with patterned agate, very rarely even amethyst or citrine crystals. Again, the larger and more unusual the better. I’ve only seen tiny white crystals in person.

 

-Treatment. Most of the agatized  dinosaur bone in jewelry isn’t treated beyond the cutting and polishing. Sometimes cracks or holes will be filled with epoxy. Collector specimens require more treatment to stabilize them, since it’s a matter of keeping a whole piece rather than selecting the best part.

 

Most of the agatized dinosaur bone I’ve worked with is at the cut an polished level, but the bones inlaid with ammolite mosaic do have a coating. Ammolite is very thin and is often coated to give it a layer of protection. With these inlaid pieces the bone has been given the same coating as the ammolite so they have the same kind of sheen and look more of a piece.

 

Agatized dinosaur bone is pretty sturdy. But it’s still very old and best treated with care. It’s not a good idea to keep it in places that will get extremes of heat or cold-like a display case facing a window, wearing it into a sauna-or worse, a place that will go from one extreme to the other-like a car. It’s also best to remove any jewelry before swimming, chlorine compounds can bleach the ancient colors.

 

So they take a little extra care, like plenty of other fossils, but it’s DINOSAUR.

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