Softer turquoise is often treated or "stabilized" to keep its luster, making it a better alternative to higher grade turquoise, which will not last as long. When ranked on this scale, turquoise jewelry stones measures between a five and a six, where low-grade "chalk" turquoise ranks as a five, and high quality stones rank as a six. Talc is considered a 1 on this scale, while diamonds are considered a 10. The Mohr's Hardness Scale is used to qualify minerals, gems and metals in terms of their hardness or density. (Lowry, Joe Dan and Joe P., Turquoise Unearthed, Rio Nuevo Publishers (Arizona), 2002) Density Many of the active turquoise mines today are in China, Iran, and the Southwestern United States including Arizona, New Mexico, California and Nevada where environmental conditions are perfect for the creation of turquoise. Because of the specific combination of conditions needed for the formation of turquoise, there are relatively few deposits throughout the world. This delicate geological process takes place most successfully in arid and semi-arid climates where surface soil and rocks are subject to erosion, and minerals can most readily be carried into underlying deposits over long periods of time. Depending on the composition of the primary deposit and minerals such as aluminum, phosphate and iron, turquoise stones of varying densities and colors are created within a host rock. Technically considered a semi-precious mineral, turquoise is formed when primary copper deposits in igneous and, to a lesser degree, metamorphic and sedimentary rock are exposed to leaching minerals in host rocks and surface runoff. Turquoise Jewelry Guide: How It Is Formed Spider-web matrix can be seen often in #8 Turquoise. One of the most popular types of matrix among collectors is the "spider-web matrix", which as its name implies, creates a characteristic, web-like appearance throughout its turquoise jewelry. The Kingman mine in Arizona yields both a common black matrix as well as a rare and highly sought-after silver matrix. For example, the earthy brown matrix of Boulder Turquoise and the tan to light brown matrix of the famous Bisbee mine are considered among the most desirable matrices found. Some mines are known for the matrix that can be found in the turquoise jewelry and the stones they are produced from. Similar to individual fingerprints, matrices vary from stone to stone, creating one-of-a-kind pieces that are visibly distinct from one another. These veins interweave throughout the stone, creating a unique pattern which contrasts with the blues, greens, earthy browns, rust, and black coloration. The matrix is formed by the thin veins of the host stone. One of the most unique characteristics of turquoise is the presence of the "matrix" in the stone. When this occurs, there is frequently a "buzz" among collectors who hope to add a unique piece to their collections. In active mines, such as the Kingman mine, new deposits are occasionally uncovered, which yield a new shade of turquoise. Some mines, such as the Sleeping Beauty mine which houses a bright, clear turquoise, tends to have high concentrations of a single color, while others, such as the Royston and Fox mines, have a wide range of hues, from light blue to deep green. Generally, the higher the copper content in a specific deposit, the bluer the stone, and the higher the iron content, the greener the stone. The color of turquoise jewelry yielded by a certain mine is a result of the metal content. Turquoise Jewelry has a wide range of colors, from deep, sea blue known as "Persian Blue", which is often found throughout the Middle East (predominantly in Iran), to bright, neon green, such as that found in the American Southwest. This Beginner's Guide to Turquoise Jewelry will provide an overview of the properties and nature of turquoise, an introduction to the variations in stones, mines and basic turquoise jewelry types, as well as our recommendations for how to select and care for turquoise jewelry. With a noticeable rise in demand for turquoise jewelry and a greater awareness of the diversity of the various types and mines throughout the world, there is a greater range of unique styles and designs of turquoise jewelry available to consumers than ever before. For over six thousand years, the Native American, Persian, Asian, and Egyptian cultures have been captivated by the alluring beauty and mystical power of turquoise.
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