Location: Western Asia
Weight: 9.39 Grams
Dimensions: 1.1 Inches Long, 0.7 Inches Wide, 0.5 Inches Thick
The item pictured is one you will receive.
Overview of Turquoise
Turquoise is an opaque mineral that exhibits a blue-to-green color, primarily composed of copper and aluminum. Its chemical formula is CuAl6(PO4)4(OH)8·4H2O, indicating that it is a hydrous phosphate. This gemstone has been highly valued for thousands of years due to its distinctive hue and rarity, especially in finer grades.
Historical Significance
The term “turquoise” originates from the Old French word “turquois,” meaning “Turkish,” as the mineral was first introduced to Europe through the Ottoman Empire. The gemstone has been known since antiquity; Pliny the Elder referred to it as “callais,” and it was recognized by the Aztecs as “chalchihuitl.” This historical context highlights turquoise’s long-standing cultural significance across various civilizations.
Properties of Turquoise
Turquoise possesses several notable physical properties:
- Color Variability: The color can range from white to powder blue, sky blue, blue-green, and even yellowish green. The blue coloration is primarily due to copper content, while iron impurities can lead to green hues.
- Hardness: On the Mohs scale, turquoise has a hardness of just under 6, which makes it softer than many other gemstones but still capable of taking a good polish.
- Luster and Transparency: It typically exhibits a waxy to subvitreous luster and is usually opaque, although some thin sections may be semitranslucent.
- Crystal Structure: Turquoise is classified as a cryptocrystalline mineral with a triclinic crystal system. It rarely forms single crystals; instead, it often appears in nodular or botryoidal forms.
Formation Process
The formation of turquoise deposits involves several geological processes:
- Hydrothermal Activity: Initially, hydrothermal fluids leach copper from host rocks—typically calc-alkaline intrusions rich in silica.
- Copper Deposition: The leached copper is redeposited in concentrated forms within fractures and joints in the rock.
- Meteoric Water Interaction: As meteoric water (from rain or snowmelt) infiltrates these deposits, it oxidizes the copper minerals present, leading to the formation of turquoise as a secondary mineral.
This process indicates that turquoise does not occur in its original form within copper porphyry but rather develops later through environmental interactions.
Market Value and Treatments
Turquoise’s value can vary significantly based on quality factors such as color saturation, matrix presence (the veining or patterning), and origin. High-quality turquoise from regions like Western Asia is particularly prized for its vibrant robin egg blue color. However, market dynamics have changed due to treatments (such as dyeing), imitations (synthetic versions), and enhancements that can affect its perceived value.
In summary, turquoise remains a gemstone of great beauty and historical significance with unique properties that contribute to its desirability in jewelry and decorative arts.
