Turquoise is one of the official birthstones for the month of December, along with Tanzanite and Zircon. It is also celebrates the 11th anniversary.
The name “turquoise” comes from the French “turqueise”, meaning “Turkish stone”, because it was first transported to Europe via a Turkish nation.
It varies in color from greenish blue, through robin’s egg-blue, to sky blue shades and its transparency ranges from translucent to opaque.
It is one of the world’s most ancient gems. Archaeological excavations revealed that the rulers of ancient Egypt adorned themselves with turquoise jewelry, and Chinese artisans were carving it more than 3,000 years ago.
The ancient Egyptians believed that the colour blue was a symbol of regeneration, so turquoise was treasured for both decorative and superstitious purposes.
It was also used by Native Americans in works of art and jewellery, some of whom believed that it possessed protective properties.
The Tibetans believe in the healing properties of turquoise and have valued the stone for centuries.
It is found in only a few places on earth: dry and barren regions where acidic, copper-rich groundwater seeps downward and reacts with minerals that contain phosphorus and aluminum.
The result of this sedimentary process is a porous, semi-translucent to opaque compound of hydrated copper and aluminum phosphate.
It owes its texture to its structure and composition. It’s an aggregate of microscopic crystals that form a solid mass. If the crystals are packed closely together, the material is less porous, so it has a finer texture.
Low porosity and fine texture are more valuable than high porosity and coarse texture. Coarse, porous stones are usually treated to make them smoother, shinier, and more marketable.
Turquoise deposits usually form in iron-rich limonite or sandstone. Limonite creates dark brown markings in turquoise. These markings are remnants of the host rock within the turquoise, and can resemble splotches or veins. They’re called matrix.
The presence of matrix can lower the value, but that doesn’t mean turquoise with matrix is worthless or unmarketable. Some buyers actually prefer the presence of matrix if its effect is attractive and balanced.
In the market for top-quality turquoise, stones with no matrix at all command the highest prices. Gems with attractive spiderweb matrix rank second in value.
It might lack the sparkle and clarity of transparent colored gemstones like ruby, emerald, and sapphire, but its multi-layered history and soul-satisfying color make it a desirable gem.
The best quality turquoise is located in Northeast Iran. Additional deposits are also found in Afghanistan, Argentina, Australia, Brazil, China, Israel, Mexico, Tanzania and the USA.
The most popular colour is sky-blue (also called “robin’s egg blue or “Persian blue”), followed by blue-green or apple-green.
Turquoise is a porous material, so it is sometimes impregnated with polymers, wax or plastic to enhance the colour and harden its surface. It’s colour is also enhanced with the use of oil or paraffin, colours or copper salt.
Imitation turquoise is made from dyeing chalcedony or howlite. Powdered turquoise is glued and glass, porcelain and plastic are used to make imitation turquoise gemstones.
Since it is a porous material, turquoise must be properly cared for in order to maintain its colour and lustre. It is sensitive to heat and if exposed to 250 degree Celsius heat, the colour will turn a dull green.
If exposed to prolonged direct sunlight, perspiration, oil, perfume, detergent or other chemicals, turquoise can suffer colour deterioration
It would be prudent to remove turquoise rings before washing hands or engaging in household chores.
Additionally, when dressing it is advisable to put on turquoise jewellery last and remove it first when undressing, to avoid exposure to hairspray, perfume or similar cosmetic products.
Turquoise gemstones should be stored separately to other gemstones to avoid scratches. Avoid exposing the material to bleach or sulphuric acid. Most stones can be cleaned using warm, soapy water. This previous article on “cleaning soft gemstones” is also helpful.
For dyed or impregnated stones, it’s best to test a small area first to ensure stability. Wipe down stones using only a soft cloth and be sure to rinse well to remove any soapy residue.
We hope this article has given you a bit more of a background on turquoise, but should you have any additional questions about this or any other jewellery related topics, you can always: “Ask the Jeweller”
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