Need-to-know Guide On Turquoise Gemstones

By Author: Alexandra
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The beautifully blue gemstone known as turquoise has been used in jewellery for centuries - from ancient Egypt and Persia to the Native American Indian culture. Historically though, the best turquoise is considered to come from Iran.
The following guide will explore the ins and outs of turquoise, including how to distinguish the fake variety from the genuine article.
How Turquoise is Valued
The properties that determine the value of turquoise gemstones are their colour, size, rarity, hardness, inclusions, treatment and final polish.
Hardness
Turquoise varies in its hardness properties. This is a critical factor to how it is the valued, so pricing will vary between the regions it is found.
Treatment, Colour & Size
The most valuable turquoise gemstones are the natural (untreated) variety with a strong “robins egg blue” colour. Although turquoise which is pale green is not considered valuable in Europe and the Middle East, it is highly valued in the Far East, Tibet and China.
Size is of course also a factor, however the larger gemstones generally have brown and yellow ...
... tones, with an uneven pattern of inclusions.
Inclusions
The formation of turquoise occurs when water flows through the earth and leaves deposits between the original minerals – this process occurs over millions of years. The turquoise and minerals then weave together to create a unique pattern called an inclusion, which can also be used to detect which mine the stone originates from.
Finish & Polish
The physical properties of turquoise can vary from stone to stone, which will naturally affect their lustre, hardness and density. The more dense and hard a turquoise gemstone is, the better the result when it is polished and it will also not scratch as easily.
Treated & Synthetic Turquoise
Turquoise has become increasingly popular and valuable over the past few decades, but there has also been an influx of treated and synthetic stones on the marketplace. In fact, 80% of turquoise has been treated to improve the colour of the less valuable stones and boost their resilience. It is becoming increasingly difficult to find genuine, high quality, natural turquoise.
While treated turquoise has a hardness similar to plastic but can be easily scratched, natural turquoise will not scratch when being cut and polished.
These are some of the main methods used in treated or synthetic turquoise to increase its value:
Impregnated Turquoise
Porous, natural turquoise is often treated with resins, epoxies or plastic to improve the quality and toughness of the stone. To ascertain whether your turquoise has been treated in this way, poke it with a hot needle and if it is plastic you will notice the signature smell.
Dyed Turquoise
Turquoise stones can be effectively dyed to enhanced or improve its colour, making it tricky to distinguish from real turquoise. The main sign however will be if there are no colour variations, since this occurs naturally in real turquoise.
Epoxy Backing
High quality, natural turquoise is rare and some stones can be thin and brittle to work with. To improve its quality and toughness, a jeweller will attach the turquoise gemstone to another stone using an epoxy. This ‘backing’ makes it less breakable and more durable when wearing. The technique is widely used by Native American turquoise craftsmen.
Reconstituted Turquoise
This occurs when small pieces of low quality or scrap pieces of turquoise are crushed into a powder and then mixed with a sticky substance called a binder. The mixture is then pressed together to form a solid mass, which is not a valuable form of turquoise.
Imitation Turquoise
This is neither natural nor treated turquoise - other materials such as dyed rocks, ceramic or plastic materials are used to look like turquoise.
Top Tests for Real (Natural) Turquoise
As mentioned above, these days there are many fake varieties of turquoise on the marketplace and they can be indistinguishable from the genuine article. Some of the main methods used for imitation turquoise are to dye howlite gemstones blue or use coloured plastics and ceramics.
Here are some simple tests for spotting fake turquoise:
· Hold the stone in your hand for several minutes and if it starts getting warm it is probably plastic, ceramic or resin – real turquoise does not heat up quickly.
· Examine the turquoise carefully for colour variations – these will naturally occur in the real variety, which is especially noticeable in turquoise beads.
· Make sure the seller gives you a signed statement that the stone is genuine turquoise, along with verification of where it was mined.
Conclusion
As can be seen, natural turquoise gemstones are rare and highly valued. Use this guide to ensure you’re not overpaying for imitations – however even the more affordable treated varieties will make for stunning jewellery adornments.
About the Author : Julia Littlewood is a stylist and jewellery designer.