An article by Lee Anderson This article explores stones (other than turquoise) that are commonly used in Indian jewelry: coral, sugilite, charoite, and gaspeite. To learn more about turquoise, read Lee Anderson’s articles. Coral Created by colonies of the marine coral polyp, coral is a calcium carbonate combined with magnesium. Originally, the best red coral […]
The History of Turquoise
An article by Lee Anderson Although turquoise has captivated man’s imagination for centuries, nobody knows when it came to our attention. Archeological and literary references to the stone predate the Christian era by five millennia. The four bracelets of Queen Zar, found on her mummified arm, date back to the second ruler of the Egypt’s […]
The Origin and Occurrence of Turquoise
An article by Lee Anderson Turquoise consists of the chemical elements copper (Cu), aluminum (Al), phosphorus (PO4), and water (H2O). It is described as a “hydrous basic aluminum phosphate of copper” or a “hydrous aluminum phosphate colored by copper salts.” Its chemical formula is: CuAl6 (PO44)8 4H2O, although this varies widely. This molecular structure permits […]
The Physical Properties of Turquoise
An article by Lee Anderson Hardness Turquoise is opaque and has a Mohs scale hardness that varies remarkably. The soft, deeply mined chalks may only slightly exceed 2 on the Mohs scale, whereas a hard, gem specimen may exceed 6. The hardness varies in response to several factors, including environment and matrix. The silicification process, […]
Natural, Stabilized, Treated, Fake, and Synthetic Turquoise
An article by Lee Anderson This article discusses various types of turquoise as they relate to the jewelry industry. Natural This turquoise comes directly from the mine. It is cut, shaped, polished, and set into jewelry. Perhaps it had only been drilled, polished, and suspended on a necklace. In any event, the stone has had […]
Turquoise Quality
An article by Lee Anderson We could write pages on this and still not cover the subject. In the earliest of times — up to the late 1800s — certainly, the pure blue without matrix was considered the best. It was time-tested; if the color did not change it was “old rock”…in other words, a […]