Z is for Zirconia

Most of you know this as synthetic diamond and probably a few of you have some of these gems at home.  They are sparkly and beautiful and can be almost any color.

It may surprise you to know that the main use of zirconia is in the production of ceramics as in dentistry.  It’s used in reconstruction, such as crowns or bridges.  Stabilized zirconia is used in oxygen sensors.  It also has potential applications as an insulator in transistors.

A brilliant cut cubic zirconia - pic courtesy of Wikipedia

When used in jewelry it has a high index of refraction and the same crystal structure as diamond.  It’s very difficult to determine the difference of a diamond and zirconia by visual testing alone.  A thermal conductivity test needs to be performed.  Diamond is a good thermal conductor where zirconia isn’t.

Y is for Yuksporite

Yuksporite - pic courtesy of Wikipedia

This is a rather pretty color mineral found in Russia.  This is a silicate mineral.  It contains rare elements of strontium, titanium and niobium, as well as the commoner metallic elements potassium, calcium, sodium and manganese.  It was found in Russia in 1922 and was named for the locality, near Mount Yukspor.

Yuksporite - pic courtesy of Wikipedia

The mineral is brownish-pink, rose pink or yellowish in color.  It has a silky vitreous luster.  Its makeup is similar to quartz but closer to tourmaline.  So far, the only occurrences of this mineral have been in Russia.

X is for Xyloid jasper

Xyloid jasper - courtesy of Wikipedia

This one is very interesting.  This is petrified wood that has fossilized.  All the original chemicals have been replaced with minerals, making a stone-like replica of the original wood.

Xyloid jasper - courtesy of Wikipedia

Xyloid jasper can be found all over the world, if conditions are right.

W is for Wulfenite

Wulfenite - pic courtesy of Wikipedia

This is found in tabular crystals with bright orange-red or yellow-orange color.  It’s found in many localities associated with lead ores.  In fact, the yellow form is sometimes called “yellow lead ore.”  Its also a secondary ore of molybdenum and is sought by collectors.

Wulfenite - pic courtesy of Wikipedia

Wulfenite was first discovered in 1845 in Austria and is named for Austrian mineralogist, Franz Xavier von Wulfen.

Wulfenite - pic courtesy of Wikipedia

Different colors of wulfenite seem to be found in different mines.  In Arizona the crystals are deep red in color.  In Mexico they’re thick tabular orange crystals and in Slovenia they’re yellow.  In 1997, the crystal was depicted on a stamp by the Post of Slovenia.

It’s soft and brittle and probably better as a crystal specimen instead of a candidate for jewelry.

V is for Vulcanite

Here is an interesting one.  This mineral is also called ebonite.  It’s a hard, moldable polished dark color of brown or black.  This was early rubber.  Vulcanite was produced by adding Sulphur to vulcanized rubber.  It was used for combs, ornaments and buttons.

Vulcanite - pic courtesy of Wikipedia

Hard rubber fountain pin bodies, hockey pucks, battery cases and mouthpieces for clarinet and saxophone are other uses for vulcanite.

U is for Uranium

This is a metal that can be used in nuclear reactors and nuclear weapons.  Uranium can also be used as a dye for stained glass and pottery.  This was the main use until people found out it was radioactive. 

Uranium - pic courtesy of Wikipedia

Uranium is a dangerous substance.  It’s silver-gray and forms a black coating in the air.  Where there is uranium you will usually see the radioactive hazard sign.  This metal can be found all across the United States. 

There are many problems with mining and milling this metal.  Many workers are exposed to high levels of radiation.  Radon gas can be inhaled by miners underground.  Accidental releases from uranium mines can also be a hazard.  Many mines are abandoned today.  This is a good thing in my opinion.

T is for Turquoise

Turquoise - pic courtesy of Wikipedia

Turquoise is an opaque green to blue mineral.  This mineral is a hydrated phosphate of copper and aluminum.  It’s been known by many names but ended up with the name turquoise because its arrival in Europe in the 17^th century was through Turkey from mines in Persia.

Turquoise is typically found in arid regions, suggesting climate plays a big part in its formation.

Turquoise - pics courtesy of Wikipedia

Turquoise was among the first gems ever mined.  The mining is done by hand in small scale operations.  It’s often discovered as a byproduct of large scale copper mining in the United States.  Copper mines are also found in Iran and on the Sanai Peninsula.  The southwest United States is a significant source of turquoise.  Sometimes in an attempt to meet demand, turquoise is treated or enhanced.  Sometimes these treatments also include  waxing or dyeing.

Even though turquoise was used in ancient times, it didn’t become significant until the 14^th century following a decline in the Roman Catholic Churches influence which allowed the stone to be used in secular jewelry.

Turquoise - pic courtesy of Wikipedia

Turquoise was thought to change color with the wearers health and protect him or her from untoward forces.

Turquoise was widely used by the Aztecs, Pueblo, Navajo and Apache tribes.  They cherished turquoise as amulets.

Turquoise - pic courtesy of Wikipedia

Turquoise is fragile and sensitive to solvents and even perfume.  Care must be taken so as to avoid contact with body lotion, sunscreen and cosmetics.  It’s also best to keep turquoise away from direct sunlight, as it can fade with prolonged sun exposure.

S is for Sapphire

Sapphire is a precious gemstone of the mineral corundum, an aluminum oxide.  Sapphire is typically blue, but natural “fancy” sapphires can be yellow, purple, orange and green, or “parti sapphires,” which are two or more of these colors.  The only color sapphire can’t be is red because red corundums are rubies.  The variety in color is from trace amounts of iron, titanium, chromium, copper, or magnesium.

This beauty is the Logan Sapphire and it weighs 423 carats - Wikipedia

Sapphires are usually cut and polished into gems and worn as jewelry although they can also be used in wristwatch crystals, high-durability windows and thin electronic wafers among other things.  Sapphire, like ruby, is also a 9.0 on Mohs scale of hardness.

A cut and polished sapphire gemstone - Wikipedia

Sapphire is graded like other gemstones, as mentioned before, by color, cut, clarity and carat weight.  The color of gemstones can be described in terms of hue, saturation and tone.  Hue is the “color” of the gemstone.  Saturation is brightness of the hue and tone is the lightness and darkness of the hue.

A beautiful teardrop cut sapphire - Wikipedia

Green or gray lessens the hue considerably and also the value.  Ideally it’s best to have violet or purple contribute to the intensity of the blue color of sapphires.

Here’s an interesting tidbit about parti sapphires.  Australia is the largest source of particolored sapphires.  These aren’t typically used in jewelry so are relatively unknown.  Particolored sapphires cannot be created synthetically and only occur naturally.

A padparadscha sapphire - Wikipedia

Naturally formed pink-orange corundum is very rare.  This type of sapphire is called Padparadscha.  This name comes from the name for the lotus flower as this is much the same color.  These stones are often from Sri Lanka.  Orange gems are often higher in price than the highest quality blue sapphire.  Because of heat treatment called lattice diffusion, more of these orange gems are being seen in the marketplace, but the naturally occurring ones are the most valuable.

Star sapphire - Wikipedia

The star sapphire exhibits a star pattern when viewed from a single overhead light source.  This star is due to rutile inclusions in the stone when it was formed.  As discussed earlier, rutile is titanium dioxide.  These gems are generally cut into cabochons (flat on the bottom) and mounted that way with the star facing outward.  The red stones like this are called “star rubies.”

Sapphire is the birthstone for September and also the gem for a forty-fifth anniversary.

R is for Ruby

Ruby from Wikipedia

Ruby is a pink to deep red gemstone from the mineral corundum.  The red color is caused by chromium.  Ruby is one of the original cardinal gems, considered precious above other gemstones.  Other gems falling into this category are sapphire, emerald, amethyst and diamond.

Natural occurring ruby - Wikipedia

The quality and price of ruby is determined by its color, cut, clarity and weight, just like the other precious gemstones listed above.  Blood-red is the most valuable color for rubies.  The stone should have good clarity too, but not be too perfect.  Inclusions are trapped inside gems when they’re formed.  Looking at one that’s perfect could indicate it’s been treated because all rubies have needle-like inclusions of rutile, a mineral that’s primarily titanium oxide. 

Cut red ruby gemstone - Wikipedia

Cut pink ruby gemstone - Wikipedia

Other than diamond and moissanite, a naturally occurring silicon carbide used in industry, ruby is the hardest gem with a reading of 9.0 on the Mohs scale of hardness.  This scale was invented in 1812 by German geologist and mineralogist, Friedrich Mohs.

Victorian ruby and diamond brooch - Wikipedia

The world’s most valuable ruby is the Sunrise Ruby, which sold in auction by Sotheby’s, in May 2015 in Geneva Switzerland, for a whopping 30.42 million US dollars.

Ruby is the birthstone for July.

Q is for Quartz

Quartz from Tibet - pic courtesy of Wikipedia

Quartz is the second most abundant mineral in Earth’s continental crust, behind feldspar.  There are many different varieties of quartz, several of which are semi-precious gemstones.  Since antiquity, varieties of quartz have been the most commonly used minerals for making jewelry and carvings.

Pure quartz is colorless and transparent.  The other colors of quartz are mixed with other minerals.  This colored quartz are semi-precious stones for making jewelry and other decorative pieces.

Amethyst - pic courtesy of Wikipedia

There are many varieties of these, but I’ll just mention a few.  Purple quartz is amethyst.  The largest deposit is found in Brazil.  Amethyst is formed when there is iron in the area.  

Citrine - pic courtesy of Wikipedia

Citrine is a variety of quartz that ranges from pale yellow to brown due to the ferric impurities.  Natural citrines are rare.  Most commercial citrines are heat-treated amethyst, or smoky quartz's.  Brazil is the leading producer of citrine.  Citrine has been referred to as “money stone” due to the superstition that it would bring prosperity.

Rose Quartz - pic courtesy of Wikipedia

Rose quartz is pale pink to rose red in color.  This is due to trace amounts of titanium, iron, or manganese.

A quartz crystal jug from the 16th century.  This piece is in the National Museum in Warsaw.  

Pic courtesy of Wikipedia

Quartz is very common in sedimentary rocks, such as sandstone and shale.  Quartz is a defining essential of granite.

Almost all of the quartz crystals used today in the electronics industry are synthetic.

P is for Peridot

Peridot is gem-quality olivine, which is a silicate mineral.  It’s one of the few gemstones that occur only in one color, olive green.  The intensity and tint of the green depends on the percentage of iron that’s contained in the crystal structure.  Peridot can occur as pure green with no yellow or brown cast.

Peridot - pic courtesy of wikipedia

Olivine is often found in lava and meteorites.  A peridot formed in volcanic activity tends to contain higher concentrations of lithium, nickel and zinc.  Olivine is an abundant mineral, but gem-quality peridot is rare.  Olivine tends to exist in a heavily weathered state, thus making it unsuitable for decorative use.

A cut and polished Peridot gemstone - pic courtesy of Wikipedia

The largest cut peridot olivine is 310 carats and is in the Smithsonian Museum in Washington, DC.

This is the birthstone for people born in the month of August.

O is for Opal

 Rough opal specimen from Virgin Valley, NV - pic courtesy of Wikipedia

Opal is classified as a mineraloid because of its amorphous character.  It’s a hydrated form of silica and may occur in fissures of almost any kind of rock, but most commonly in limonite, sandstone, rhyolite, marl and basalt.  Opal is the national gemstone of Australia.

Opal from Australia - pic courtesy of Wikipedia

The internal structure of opal makes it diffract light.  It can take on many colors, but usually is clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown and black.  Black opals are rarest.  White and green opals are the most common.

Opal mined near Queensland Australia - pic courtesy of Wikipedia

Opal was rare and very valuable years ago.  In Europe it was a gem prized by royalty.  Today the state of South Australia accounts for about 80% of the world’s opal.

Showing the "fire" in opal - pic courtesy of Wikipedia

Opal pendant from Ethiopia - pic courtesy of Wikipedia

In the Middle Ages opal was considered a stone that could bring good luck.  It could also confer the power of invisibility, if wrapped in a fresh bay leaf and held in the hand.  

In Sir Walter Scott’s novel, Anne of Geierstein, opal acquired the reputation that it held supernatural powers.  In the novel, the Baroness of Amheim wears it as a talisman.  When holy water drops on the necklace, the opal turns into a colorless stone and the Baroness dies shortly thereafter.  Due to the popularity of this novel people began to associate opal with bad luck and death.  This had a great impact on the opal market.  Within a year of publishing Scott’s novel in April 1829, the sale of opals in Europe dropped 50% and they remained low for the next twenty years.

Opal is the birthstone for people born in the month of October.

N is for Nickel

Nickel is considered corrosion-resistant, but it will slowly oxidize by air at room temperatures.  It was used for plating iron and brass, coating chemistry equipment and manufacturing certain alloys that retain a high silvery polish.  About 9% of nickel production today is still used for corrosion- resistant plating.  It’s also been used to make coins, but in recent years is being replaced with cheaper metals.

Nickel most often occurs in combination with iron and Sulfur.  Nickel is commonly found in iron meteorites.  Australia and New Caledonia have the largest reserves of nickel.

Nickel coins - pic courtesy of Wilkipedia

Aside from some very early coins, nickel wasn’t a component of coins until the mid-19^th century.

Nickel pic courtesy of Wikipedia

About two million tons of nickel is produced annually worldwide.  The Philippines, Indonesia, Russia, Canada and Australia are the world’s largest producers of nickel.  

Hydrated nickel sulfate crystals - pic courtesy of Wikipedia

Nickel is used in stainless steel, rechargeable batteries, electric guitar strings, coins, and plating on plumbing fixtures.

Nickel is the top confirmed contact allergen worldwide, partly due to its use in jewelry for pierced ears.  Many earrings are now made without nickel, or with a low-release nickel.  Contact dermatitis is marked by itchy, red skin and affects nearly 72.29 million people.