I have some very good news for all of you born in August. Just recently, the American Gem Trade Association and Jewelers of America announced that SPINEL has been added to the birthstone list as an alternative to peridot. Not everyone is a fan of peridot’s yellowish-green color, and the gem stone has a narrow range of hue. Spinel, on the other hand, comes in almost every color of the rainbow! The most prized color is red. Pink and blue are two other popular hues. So, because spinel is a relatively unknown gemstone and because changes to the birthstone list don’t happen often, it seemed important to write about it.
Many people have never heard of spinel. It was recognized as a separate mineral about 200 years ago, but, until then, red spinel was often mistaken for ruby. Some famous gems, like the Black Prince’s Ruby, which is set in England’s Imperial State Crown, are actually red spinel. Those who have heard of it often associate it with something “cheap” or “common.” Synthetic (aka man-made) spinel has been used for years to make the stones for high school class rings because it’s inexpensive to produce in lots of different colors that mimic birthstones like emerald, ruby, and sapphire. Synthetic spinel is also used as the top, bottom, or both of a “triplet” that substitutes for a natural gemstone.
Natural spinel is a beautiful mineral made of magnesium, aluminum, and oxygen. It’s colorless unless a trace element such as chromium, iron, or cobalt makes its way into the recipe. Chromium leads to a pink or red spinel. Iron and cobalt lead to violet and blue spinels. A combination of trace elements produces orange or purple spinels. These colors need no enhancement, so spinel is rarely heat-treated or irradiated. It’s a fairly hard gemstone, scoring 8 on the Mohs Scale, and it forms in the cubic crystal system. These qualities mean that spinel is hard enough to take a good polish and easy enough to cut and facet. And the gem is usually eye-clean when it comes to inclusions.
Spinel is traditionally associated with Asia–especially Myanmar, Vietnam, and Sri Lanka. More recently deposits have been found in Tanzania and Madagascar. Large crystals are quite rare, so the value goes up exponentially, not only for great color but also for size. While not as expensive as fine ruby or pink sapphire, natural spinel is not an inexpensive gem. Red spinel would cost approximately 30% of the cost of a similarly sized ruby. And pink spinel would be about 85% of the cost of a same size pink sapphire. It’s not easy to find spinel in a jewelry store. Maybe that will change now that it’s a birthstone, but, up until now, it’s been more of a collector’s stone.
So, take heart all of you who longed for another birthstone! It’s spinel to the rescue!! Ask your jewelry store for a peek at its spinel. Here’s a peek at ours.
1.28 carat pink spinel
Flawless Quartz Crystal Sphere at the Smithsonian Natural History Museum (106.75 lbs)
This crystal sphere is the largest cut piece of flawless quartz in the world, weighing in at 242,323 carats! It symbolizes our fascination with something so beautiful and yet so common. Quartz is found around the world, in large quantities, and is considered one of the most common minerals on Earth. It’s found in sand, dirt, and dust. Yet, when fashioned by gem cutters and put in a stunning piece of jewelry, it can be breathtaking.
Quartz is a complicated gemstone. One of the reasons it’s tricky is because the term “quartz” is used for varieties of gems, as well as for a species of gem and as a group of gems. So, for example, Rose Quartz is a variety of the species Quartz. So is Citrine, Amethyst, and Tiger’s Eye! All these varieties, and others that are couched under the species of Chalcedony, such as Agate and Jasper, are considered to be members of the group, Quartz. Very confusing!!
Perhaps it’s best to start with the fact that mineralogists and geologists see any mineral with the chemical makeup of silicon dioxide, SiO2, as Quartz. Regardless of whether the crystals making up that stone are large, small, or microscopic, it’s all Quartz. Gemologists, on the other hand, separate the gems into those whose crystals are larger and those too small to see without a high-powered microscope. Those with larger crystals are called Quartz and those with microcrystalline structures are labeled Chalcedony.
Under these two species are many varieties that are used in jewelry. Probably the most commonly known variety of the quartz species is Amethyst. That regal purple has been admired for centuries. The purple color comes from natural irradiation acting upon a trace element of iron. The saturated, medium to deep reddish purple is the most prized color, but amethyst ranges from a light, pinkish purple to that deep purple hue. Amethyst is not rare, but the prized color is more rare because usually only the tips of the amethyst crystals have that depth of color.
Agate and Amethyst, showing the deep purple tips of the quartz crystals, as well as the microcrystalline Agate, which is part of the Chalcedony species.
Other varieties of the Quartz species include Citrine, the orange-yellow gemstone that’s November’s birthstone, and Rock Crystal, which is colorless because it has no trace elements. There’s also Rose Quartz, Smoky Quartz, Prasiolite (aka Green Amethyst), and Ametrine (a bi-colored gem combining the purple of Amethyst and the yellow of Citrine).
Members the Chalcedony species have been used in jewelry even longer than Amethyst! Agates, which exhibit wavy bands of color, were used in amulets and talismans over 3000 years ago. They were also used to make cameos. Carvers would reveal a differently colored band by carving down around the subject of the piece. Today you’ll see agate slice pendants that are sometimes dyed to accentuate the banding.
Probably the most valuable member of the Chalcedony species is Chrysoprase. This translucent gemstone is beloved for its natural apple-green color. It owes its color to the presence of nickel. A big discovery of Chrysoprase was made in 1965 in Australia. Because its color can resemble fine jadeite, it’s sometimes called “Australian Jade.”
Other varieties of the Chalcedony species include Black Onyx (dyed black chalcedony), Carnelian, Jasper, and Fire Agate. Most chalcedony is translucent to opaque, so it’s rarely faceted. Most often it’s fashioned into beads, slices or cabochons. But, just like all Quartz, it registers a 7 on the Mohs Hardness Scale, making it a good choice for rings and bracelets as well as earrings and pendants.
There’s so much that can be said about this beautiful mineral that surrounds us everyday. But I want to end with the sentiment– “How wonderful when something so common can also be so special!”
Custom-made Ametrine Ring in our showcase!
I’ve lived most of my life in Michigan and my maiden name is Campbell. Most people don’t know that because I’ve been married so long! But I always thought Campbell was a good name, so I was both happy and surprised to learn that there is a gemstone named after. . .no, not me, nor my kinfolk, but after the Campbell shaft of the well known Bisbee Mine in Southern Arizona.
So, what’s the story of Campbellite? As explained by one of the stone cutters at Arizona Lapidary, Campbellite is an uncertain mixture of minerals like cuprite, azurite, malachite, calcite,chrysocolla, pyrite, quartz, and copper. Its color and look varies because there’s no set amount of these minerals. It was first discovered by miners looking for copper. The bosses weren’t interested in this unusual rock, and told the miners to discard it. But the miners had a different plan. They saw its beauty. So, yes, they dumped the Campbellite in the trashcan. But they separated it carefully from the real trash. And when no one was looking, they loaded the discarded gem into the back ends of pickups. Campbellite has been showing up in the market, piece by piece. There’s not a lot of it–I’m sure plenty WAS dumped. The mine closed in 1975, and there is no other known source of Campbellite. But I bought one piece of it, cut into a smooth cabochon, and plan to make a bolo tie for my dad.
I learned a little bit about the mine shaft itself. It was first developed in 1927, originally as a way to get oxygen to other parts of the Bisbee Mine. But soon it was one of the best producers of copper ore, with yields of 8-10% copper.
Finally, who is the Campbell shaft named after? A little research revealed an amazing coincidence. The shaft was named after Gordon R. Campbell, who actually lived and went to school in Michigan! He graduated from U of M in 1893 and was a mining executive and lawyer up in the Keweenaw Peninsula. The Keweenaw Peninsula, jutting from the Upper Peninsula of Michigan, is one of the best known sources of copper world-wide. Towns like Calumet, Houghton, and Copper Harbor were booming back in the mid-1800s because of copper. Anyway, Gordon Campbell helped form the Calumet and Arizona Mining Company in 1901, serving as the company’s President from 1921-1931. It was this company that operated the Bisbee Mine. So Campbellite WAS named for a Campbell living in Michigan. Who knows? Maybe he’s a long, lost cousin?
The Campbell shaft, courtesy of the Arizona Historical Society
The other day a customer came in to get her ring sized. She was amazed and somewhat alarmed to learn that our bench jewelers would be cutting her ring with a saw blade in order to size it. Her beautiful ring–a piece of art–subjected to the saw! But jewelry is more than art and more than an expression of sentiment. It’s also a piece of engineering. It’s built with shanks and prongs, bails and bezels, and many other findings. It’s adjusted or repaired with the use of tools like saws, hammers, and torches. Using rings as our example, let’s explore the Anatomy of a piece of jewelry.
MOUNTING: This is the general name for the metal that holds the stone(s) in place and encircles your finger to keep the ring on your finger.
SHANK: This refers to just the curved part of the ring that goes around your finger. Shanks can have profiles(or cross-sections) that can be quite flat to very round. The width of the shank can also vary. And the shape of the shank, while usually circular, could be oval or even rectangular. A EURO-SHANK is curved on the sides but has a squared off bottom. There are adjustable shanks, too, which operate with hinges, allowing more room for a ring to slide over the knuckle.
SETTING: Sometimes a synonym for mounting, a setting probably refers more to how the stone(s) are held in place. Setting techniques include prong or shared prong set, bead set, tension set, channel set, bar set, flush set, bezel set, pave set, and invisible set.
PRONG: Tiny metal wires that suspend the stone, holding it in little “claws” (HEAD), so that light can enter the diamond from all sides.
BEZEL: A frame of precious metal that surrounds the stone, bezels can be thin like a wire or wide so that the side of stone is unseen.
FINISH: Whether the metal is shiny or more dull depends on the finish. You can have a polished finish, which is shiny or a matte finish, which is smooth but less shiny. Other finishes like satin, hammered, engraved or stone can give texture to the surface of the ring.
MILLGRAIN: This is a common embellishment on the shank of a ring. It’s a border of tiny beads that acts as a boundary or edging.
I could go on–there seems to be about ten- thousand terms that bench jewelers use. I learn a new one almost every day. Instead, let’s re-cap with a picture and save Anatomy 102 for another day. The important thing to glean from today is that jewelry is a designed and constructed piece of art. It’s engineered to be art that you can wear.
Engagement Ring with an Engraved Finish