Quartz-So Common and yet so Special

Flawless Quartz Crystal Sphere at the Smithsonian Natural History Museum (106.75 lbs)

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.

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.”

Chrysoprase cabochon

Chrysoprase cabochon

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!

Custom-made Ametrine Ring in our showcase!

 

Common Gemstone Treatments–Heating, Irradiating, and Bleaching

The Earth is very hot–over 10000 degrees Fahrenheit at its core.  Over the millions of years that gemstones formed in the earth, some have been subjected to high temperatures.  Interestingly enough, this heat can alter the light absorption of the stone, changing its color.  Sometimes heat “improves” the color of the stone, perhaps taking a gray, brown, or almost colorless stone and turning it to a cheerful blue or a regal purple.

Man has found a way to heat stones that Earth neglected to heat.  The most common types of heat treated gemstones are ruby, sapphire, topaz, tanzanite, and zircon.  If you buy one of these stones, you can be quite certain that it’s been heated by man.  You’d pay a huge premium to have beautiful color without man-made heat.  The time spent heating, the temperature, and the other treatments that may be combined with heat will all vary depending on the raw material.

non-heat treated tanzanite on the left and heat-treated tanzanite on the right

Non-heat treated tanzanite on the left and heat-treated tanzanite on the right

 

Our planet also naturally irradiates stones.  Irradiation can change the arrangement of the protons, neutrons, and electrons that make up the atoms of the stone.  This can alter the color of stones as well.  Man has figured out how to irradiate gemstones in order to improve color.  They can be treated to high energy radiation at a gamma ray facility that uses cobalt-60 so that there is no residual radioactivity.  Diamonds are sometimes irradiated to create beautiful fancy colored diamonds.  Colored diamonds can occur naturally, but it’s rare for them to be blue or green.  That’s why famous gems like the Hope Diamond or the Dresden Green are so amazing.   If you see a blue or green diamond, chances are man has irradiated it.  Blue topaz is another irradiated gem stone.  It’s the combination of irradiation and heat treatment that brings out that beautiful Swiss or London Blue in topaz.

The sun gave us inspiration for bleaching.  Stones often look prettier if they are whiter or less brownish.  Pearls and jadeite are both commonly bleached–and not by the sun. The process involves hydrogen peroxide or some type of acid.  Pearls, even if they are natural in color rather than dyed, are still often bleached to lighten and brighten the color nature gave them.

Unbleached jade on the left and bleached jade on the right

Unbleached jadeite on the left and bleached jadeite on the right

 

Most people in the jewelry industry accept these three treatments.  Since heating, irradiating, and bleaching could have all occurred naturally, it seems that man is helping out by making a natural process accessible to more gemstones.  And since all of these treatments are permanent, no one has to worry about their gemstone changing over time.  Finally, without these treatments, colored gemstones and pearls would be much more expensive and exclusive.

Our final post of this series will be about treatments that are not as commonly accepted.  These are treatments you, as the consumer, should definitely be aware of before you buy.  Treatments such as surface coating and fracture filling can enhance the look of the stone but may not be permanent.  Remember to ask questions if you want to know about treatments on a gemstone you’re planning to purchase.

 

 

 

 

 

Why Start with D? A History of Diamond Grading

Round Brilliant diamonds of different sizes.

Most couples looking for a diamond engagement ring are already familiar with the color scale for diamonds.  They know that “D” is the “best” if you want a colorless diamond.  It’s just accepted.  But why start with D?  There are historical reasons why color grading doesn’t start at the beginning of the alphabet.  The story is interesting, but basically boils down to the struggle between metaphoric or geographic vs. scientific description.

In the late 1800s, when diamonds and diamond mines were being discovered and dug in Cape Province, South Africa, there was little consistency in the description of diamonds.  Diamond brokers came up with various ways to grade diamonds, using I, II, and III or A, B, and C to indicate quality.  Later, AA and AAA were used to indicate even higher quality than A.  There was a wide range of diamonds that fell into each quality designation, and the grade often depended on who was doing the grading.  There was no set grading system that everyone agreed to follow.   The goal was to sell diamonds, so grade inflation was common.

Some grading terms were even more vague than A, B, and C.  Old world terms for colorless diamonds included “River”, “Finest White”, and “Jager.”  Where do these terms come from?  River was meant to indicate the clear, as water, nature of a colorless diamond.  Jager was a nickname for the Jagersfontein Mine in South Africa, a mine known for the exceptional quality and clarity of its diamonds.  This mine was also known for producing two of the biggest diamonds ever found, the 972 carat Excelsior and the 637 carat Jubilee.

In the 1930s, when the Gemological Institute of America(GIA) was first established, it focused on the science of gemology and the importance of education.  Eager to bring more consistency to diamond grading, the GIA developed its international diamond grading scale in 1953.   It wanted to clearly separate its scale from existing scales.  The GIA started with D so as not to be confused with the A, B, and C grades that already existed in other, less consistent scales.  That’s why the scale starts with D and goes through Z for the normal color range of diamonds.  The GIA scale is much more scientific, with more grades and a set of master stones to represent each color grade.  Skilled graders compare stones to this master set under specific lighting conditions.

The American Gemological Society(AGS) has a numeric as well as letter grading system, with D equal to 0.0, E equal to 0.5, F equal to 1.0 and so on.  Both the GIA and AGS use descriptive words to go along with their grades so, for instance, grades of D, E, and F are described as colorless while grades of S through Z are described as light yellow.  If a diamond is more yellow than the Z master stone, it’s actually a fancy colored diamond and is graded using a different system.

So it was those diamond sellers back in the 1800s that shaped the system we have today.  Even with the unusual starting point, consumers should be grateful for the consistent grading that the GIA and AGS provide.

 

How to Care for Organic Gemstones

pearls

Gems like pearl, coral, ivory, shell, or amber have very different beginnings than inorganic gemstones like ruby or diamond.  Organic gems were formed from biological processes and, though they are strong enough to be set in jewelry, they require special care and cleaning.

When cleaning your jewelry, never use harsh soap or chemical jewelry cleaner on organic gems.  Don’t use an ultrasonic cleaner or steam cleaner.  You can dampen a soft cloth, like flannel or microfiber, with water or mild soapy water, and run the cloth over the gems.  Then you should dry quickly with another clean, soft cloth.  Never soak an organic gem because of its porosity.

Organic gems shouldn’t be subjected for long to strong light or heat.  Drastic changes in temperature or humidity are bad for them as well.  Sunlight can bleach gems like ivory, destroying the yellow patina which shows age and makes the ivory more valuable.  Heat and high humidity can cause crazing or discoloration.

At the same time, too little humidity is bad for organic gems.  If your gems are very dried out, you can hydrate them with a little mineral oil.  Some people recommend doing this once a year.  Put it on and take it off with a soft cloth.  Do not soak it in mineral oil, but, if the piece is very dehydrated, you can wrap it in a cloth dampened with mineral oil, and let it sit overnight.  Just make sure to wipe off any excess oil in the morning.

Human oils are moisturizing for organic gems.  But when you remove your jewelry, it’s best to wipe it down with a clean cloth.  Put jewelry on after you’ve put on your make-up, hairspray, and perfume.  And don’t wear these gems if it’s a really hot day–sweat has a chemical component to it that can stain some organic gems.  If you’re going to be cooking, cleaning or doing any activity involving vinegar, bleach, or detergents, take your jewelry off.

Finally, when storing your jewelry, it’s best to keep organic gems in a protected soft pouch or tissue paper to protect them from being scratched.  Do not, however, store them in a plastic pouch.  The plastic can emit a chemical that can cause a pearl’s surface to deteriorate. Storing jewelry in a safety deposit box or safe can dry out organic gemstones.  Place a small container of water in the lock box, and be sure to open the box regularly to allow air circulation.

After all this, it may sound like organic gems aren’t worth the work!  But once you get in the habit of caring for your organic gems, it won’t seem like work.  They are definitely worth the extra care!

coral

 

 

 

 

What IS It About Sapphires?

sapphire1

Many of us know that Sapphire is the September birthstone.  It’s also the precious gem suggested for the 5th and 45th wedding anniversaries.  But, what IS it about sapphires that makes them so special?  Considered one of the four most precious gems–the others being ruby, emerald, and diamond–sapphires have been prized since ancient times.

If you think of sapphires in chemical terms, Al2O3, they don’t seem like much.  Aluminum and oxygen are two of the most common elements on Earth.  Even the trace elements, iron and titanium, the ones that make sapphire blue, are not exactly precious.  Sapphires form in coarsely-grained igneous rock in many places such as Brazil, Tanzania, Sri Lanka, Thailand and Australia.  They don’t seem like the gemstone of royalty.

It is true that sapphires require the exact combination of elements and  slow-cooling temperatures are a must.  Mining these gemstones isn’t easy.  And there are few hues as beautiful as the cornflower blue of a fine sapphire.  But part of sapphires’ prestige is the deeper meanings attached to it over the centuries.

When you read reports on all that sapphires symbolize, it gets very confusing.  How can one stone represent seemingly every good thing in the world?  The skeptic in me starts to wonder–but, in my desire to be open-minded, I’ve come up with a theory.

In Biblical times, the blue color of sapphire symbolized heaven or a call for heavenly blessings.  Maybe because religion and mysticism were such a big part of life in those times, anything “celestial” signified hope and faith.  The sapphire represented a seeking of spiritual truth.  Royal and holy men believed the stone brought them the gift of prophecy and divine favor.

From there, people began to think the sapphires could help them see truths of all kinds.  It was a stone of wisdom, intuition, and mental clarity.  With clear vision in hand, one can accomplish many of the major goals in life.  So the sapphire was seen as the stone of love, peace, and joy.  It could relieve depression and ease anxiety.

Given all the amazing things that sapphires can bring, everyone should own one!  Especially if you’re born in September.  Regardless of whether you believe in the spiritual gifts of this gemstone, sapphires are one of nature’s gifts to us.