A to Z 2022, Blog

U is for Unakite – #atozchallenge

U is for Unakite

If you have been to the Smithsonian in Washington, D.C., you may have seen or actually walked on unakite without realizing it. You will find unakite on the mall-side terrace of the Natural History Museum. Unakite is a metamorphic form of granite altered by orthoclase, epidote, and quartz. It is a strong mineral (a 6 – 7 on the Mohs scale) which makes it suitable for building although it is predominately used where aesthetics are important.

Unakite was identified in 1874 by ETSU geologist Frank Bradley. It was named after the Unaka Mountains which run along the border of North Carolina and Tennessee. It has a very distinct color pattern of greens (epidote) and pinks (orthoclase). In addition to its use in construction, it is a wonderful material for lapidary or carving work. It also polishes nicely and has no known toxicity concerns.

While discovered along the Tennessee / North Carolina border, unakite can be found in other places throughout the world. This particular piece was found in New Jersey and is on display at the Smithsonian. It gives you a good sense of using this stone for more ornate architectural purposes.

Courtesy of the Smithsonian under Creative Commons Zero (CC0) License

Unakite is often sold as tumbled/polished stones or pre-cut cabochons or beads. Lapidary slabs are easily available and affordable.

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A to Z 2022, Blog

T is for Turquoise – #atozchallenge

T is for Turquoise

My apology to anyone who received my premature ‘draft’ of this post yesterday. I lost all of the post I was writing, so I’m starting fresh.

I have always loved turquoise. My step-sister sold turquoise jewelry back in the 70’s. It always had a great energy to me. When my husband and I traveled to Santa Fe, I went to a few antiquity markets hoping to buy an authentic antique Native American turquoise ring. I found a plethora of them, but purchasing one was not meant to be. Not because I couldn’t afford it, but because none of them would fit. Our hands and fingers are much larger now or else the people who wore these ring were much smaller in stature. One of the shopkeepers suggested I check out one of the authentic Native American shops.

Sterling silver with 15 turquoise beads

We went into a Zuni shop and it was a sight to behold. The craftmanship was amazing and the fair trade policies and authenticity were appealing to me. I found a beautiful ring set with fifteen tiny turquoise stones. I fell in love with it. One day I noticed I lost one of the stones. I was heartbroken until I found that tiny little turquoise at the bottom of my purse. I have since repaired it, but rarely wear it for fear the stone may come loose again. I did not want to glue it in place.

Turquoise is a hydrated phosphate of copper and aluminum and ranges in color from blue to green. It was one of the oldest gemstones known to have been mined for adornments. The Aztecs and Incas favored the colors as did the Native Americans. The copper impurities turn the stone blue and the iron impurities turn the stone green. Archaeological digs have dated turquoise adornments back to the time of Aztec kings and Egyptian pharaohs. Even Tutankhamon’s burial face mask includes turquoise along with other gemstones.

Sadly, American turquoise is fast becoming a depleted mineral. Many of the turquoise mines in the U.S. have shutdown resulting in gem quality turquoise becoming a more rare gemstone. Turquoise fakes, liked dyed howlite, are often sold as turquoise – there is no honor among thieves. Another case of buyer beware. There is an abundance of turquoise mined in China, however much of it has been filled with epoxy to stabilize it, or it has been enhanced to deepen the color. There is also an abundance of compressed or composite turquoise on the market, made up of smaller pieces joined together to create a larger stone.

Turquoise cabochons in matrix – gift from a friend

The more pure the color in turquoise, the more valuable. Much of the available turquoise on the market is “in matrix” meaning there are dark web-like veins of the host mineral running through the stone. I prefer turquoise in matrix myself. Turquoise is somewhat soft, a 5-6 on the Mohs scale. It is also a porous material which makes it vulnerable to chemicals, perfumes, oils from the skin, and extreme sunlight. There is no industrial use for turquoise.

The most recognizable Native American jewelry piece must be the squash blossom necklace. The ornate design and use of silver (often from melted down silver dollars or pesos) and turquoise were worn to show wealth and position. The necklace has three parts, the beads, the ‘blossoms’ and the upside down crescent shape called a naja. This diné (Navajo) piece is in the collection of the National Museum of the American Indian in Washington, D.C.

A to Z 2022, Blog

S is for Spinel – #atozchallenge

S is for Spinel

I like to refer to spinel as the ‘great pretender’. Why you ask? Well, spinel has been mistaken for other important stones throughout history and frankly, it has gotten a bad rap because of it.

Spinel, like some other gemstones, is clear in its pure state. It is a magnesium aluminum oxide created when heat and pressure alter impure limestone. It is often found in the same locations as rubies and sapphires. It was not until 1783 that spinel was declared a separate mineral from corundum (rubies and sapphires).

Spinel’s bad rap came from the fact that many highly regarded rubies and sapphires were later identified as spinel, in the British Imperial Crown, for example. The Black Prince’s Ruby (now known as a spinel) has quite a storied history. The spinel’s reputation is improving, however. As more and more enhancements are made to rubies and sapphires to enhance their color, pure spinel gems are gaining in value and appreciation.

A spinel crystal has eight sides, known as an octahedron. It looks like two four sided pyramids joined at the base. It is highly refractive and is found in a variety of colors depending on the trace elements contained within the crystal structure. Colors include red, orange, blue, purple and even black. A color range can be striking as seen in the photos below. These 32 gems were mined in Vietnam and are now part of the permanent collection at the Smithsonian

Courtesy of the Smithsonian under Creative Commons Zero (CC0) License

Spinel has recently been added as an alternative birthstone for August so if you don’t like green, you now have an alternative. That’s industry marketing for you. The stone facets beautifully and is durable measuring at 7.5 – 8 on the Mohs scale. There is no known toxicity so it is a fairly safe gemstone to work with. I could find no uses for spinel other than as a gemstone.

Red and blue high quality spinels are the most sought after.  A 6×9 mm high quality red or blue spinel comes in between $1200 – $3400 depending on the cut, clarity, weight, etc. Still a pricey stone.

A to Z 2022, Blog

R is for Rhodochrosite – #atozchallenge

R is for Rhodochrosite

The first time I was introduced to rhodochrosite was in my lapidary class. One of my fellow students was struggling to get a polish on a piece of the pink and white material. It was the first pink ‘rock’ I had seen. She purchased a slab (a mineral that has been cut into a slice but not shaped or polished) from a man at the local flea market. I even went to the flea market to try to find him to no avail.

Rhodochrosite is otherwise known as manganese carbonate, a minor ore of manganese. Manganese is an important mineral for the human body and is available naturally through leafy greens, beans, nuts, etc., and is included in most multi-vitamin supplements.

As a gemstone it can be a deep pink, or more frequently a banded stone with varying degrees of the color pink and often containing some streaks of brown. It is a relatively soft stone (the reason my fellow student was having a difficult time achieving a polish) coming in at a 3.5 – 4 on the Mohs scale. It is rated as having low toxicity although I have read it can contain trace amounts of lead.

Let’s take a minute and talk about safety and common sense. Unbelievable as it may seem, I have read an article or two advocating making elixirs by soaking minerals in water and consuming them.  DO NOT DO THAT. Minerals are intertwined with so many elements and other minerals (many being toxic) it is an extremely risky practice.

This is a beautiful crystal specimen of rhodochrosite mined in Colorado. It is part of the mineral collection in the National Museum of American history.

Courtesy of the Smithsonian under Creative Commons Zero (CC0) License

This video shows some highly polished rhodocrosite cabochons. This is the color patterns most often seen. Finding pure pink rhodochrosite is rare.

A to Z 2022, Blog

Q is for Quartz – #atozchallenge

Q is for Quartz

I had to chuckle while researching quartz for today’s post. This line taken from gemologyonline.com is a perfect way to explain the claims and assertions any of us can find online:

“In modern times quartz has been credited with the ability to do everything.”

That just about sums it up! Seriously, though, quartz is one of the most common minerals found on earth, but don’t let that fool you. It is also the mineral group that contains some very valuable gemstones, too, like citrine, amethyst, and emerald. Many people are also fond of rose quartz, a lovely pink gemstone. I often get requests to wire wrap rose quartz.

When I first started making beaded jewelry, I bought a strand of rather large quartz beads. The first necklace I made (center in the photo below) always made me think of Wilma Flintstone’s chunky necklace. Everyone loved it though. I even had a commission to make a number of them for a wedding, but unfortunately could never find the large beads again.

Quartz has many industrial uses. It is used to make glass, watches, kitchen countertops, paint, sharpening tools, electronics, ceramics, and even in fracing in the petroleum industry. (This is a good time to talk about buying and selling property. Some people sell off the mineral rights to their property. This means if you buy the land, you may not own what lies beneath the soil. The world gets more and more complicated.)

Recently the Smithsonian was gifted an 8,000 pound 7 ft high slab of quartz crystals mined in Arkansas in 2016. Appraised at approximately $3.5 million dollars in 2018, it is an exquisite specimen. If you are a geeky nerd like me, you might enjoy this video about the Berns Quartz (named after the donors) and how it came to be gifted to the museum.

Quartz dust can cause silicosis for which there is no cure. It is therefore rated high on the toxicity scale. The mineral has a rating of 7 on the Mohs scale, so it is a strong material. Crystals should be stored separately, though, to prevent the tips from breaking off if contact is made with other crystals.