Turquoise Quality Factors


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The green turquoise cabochon, from an American mine, might become part of a designer’s unique jewellery piece. The even blue colour of the cabochon on the right would be called Persian blue in the trade.
Excellent-quality turquoise is sought after around the world by designers of unusual jewellery pieces.

Typically, whether a fashioned turquoise meets the ideal or departs from it, it’s judged on three basic qualities—its colour, its texture and the presence or absence of matrix.

Colour
The most-prized turquoise colour is an even, intense, medium blue. But some consumers prefer a greenish blue, and some contemporary designers actively seek avocado and lime green turquoise.

Turquoise Brooch and Graduated Bead Strands
The turquoise in the brooch and graduated bead strands is from Arizona’s Sleeping
Beauty Mine. Its smooth, even colour represents the appearance prized by most collectors.
- Courtesy GLEAM
Clarity
Turquoise can be semitranslucent to opaque, with a colour that usually ranges from light to medium blue or greenish blue. It’s often mottled, and sometimes has dark splotches. It might also have veins of matrix running through it (matrix is a remnant of its surrounding rock). The material known as spiderweb turquoise contains fine seams of matrix that form attractive web-like patterns.

Freeform turquoise cabochons
These free-form turquoise cabochons show a typical matrix pattern.
The most valuable turquoise is an even medium blue, with no matrix and the ability to take a good polish.

Cut
Turquoise is most often fashioned as a cabochon. The smoothly rounded dome shape sets off turquoise’s colour, texture and any matrix beautifully. In addition, manufacturers and artisans fashion turquoise rough into round or oblong beads for strand necklaces, and into small, flat pieces that are popular in jewellery inlays. Some top-colour blue turquoise is engraved with Persian or Arabic inscriptions, inlaid with gold. Other rough material might be tumbled into “nuggets".

“Pegged Nugget” turquoise bracelet
This stylish and unusual “Pegged Nugget” bracelet contains about 100 flat turquoise nuggets that are attached with flat silver pegs. - Gift of Robert Lee Morris
Intarsia box
This intarsia box created by Nicolai Medvedev includes flat pieces of turquoise as part of its inlaid design. - © GIA & Tino Hammid, gift of Carol and Fred Seeman
Carat Weight
Turquoise is available in a wide range of sizes. All sizes, even very small ones, are used in Native American jewellery, and large sizes have been popular for carvings. For any size, the quality and evenness of the colour is the overriding value factor.

Turquoise Rough and Gem Pieces
A single large piece of rough can yield much smaller pieces of fine, evenly coloured
turquoise. A gem cutter has to work around the host rock to avoid ending up with a much
less valuable gem.