With the high popularity of turquoise, chances are that you already own a piece of turquoise jewelry, or are considering buying your first
silver turquoise pendant, or earrings, or necklace. When you contact an online or local seller to start the process, he or she will likely explain to you in some detail, the varieties types of turquoise that is available to you. Many of these terms may seem a bit strange and confusing to you. This article seeks to provide a simple guide to the various terms used to describe turquoise in the market.
The first step in this process is to gain a rudimentary understanding of the origin and properties of turquoise. The formation of turquoise commenced tens of millions of years ago when phosphates of copper and aluminum in the right proportion were subjected to high heat and pressure under geologic or tectonic forces. Molten silica entered the mix and helped fuse the compounds together. In some cases, the process of silicification was extensive and the resulting turquoise was hard and durable. In most cases however, silicification was not complete, and the resulting turquoise specimens were porous and soft. With this background, let's delve into the categories of turquoise available in the market today.
In cases where the silicification was complete or nearly complete, the turquoise had a high density, was hard, and today can be used directly in jewelry after just cutting and polishing. This type of turquoise is said to be gem-quality, and represents the best quality of turquoise available in the market today. Gem quality turquoise is very rare (less than 5% according to some estimates) and quite expensive. Iran is famous for its consistent production of gem quality turquoise. Some of the mines in Arizona such as the Bisbee, Kingman, and Morenci mines are also know for the gem quality turquoise that they produced in the past. Since gem quality turquoise is this rare, it costs a lot!
Most of the turquoise in the market today has been treated to improve its visual and/or physical properties. The most basic treatment is to take a piece of low to moderate quality turquoise, and coat the surface with either vegetable soil or paraffin wax. This treatment may temporarily improve its appearance but does little to enhance its physical strength and durability. To achieve this, a more sophisticated approach called stabilization is needed. Here, turquoise of moderate quality is infused with epoxy resin or silica vapor. This treatment is permanent and improves the density and strength of the specimen. Stabilized turquoise is considered to be genuine turquoise by the jewelry community. Stabilized turquoise is much more affordable compared to gem quality turquoise. The turquoise beads in your
white pearl necklace are in all probability, stabilized turquoise.
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