mineral

Turquoise and Red Coral

Turquoise: CuAl6(PO4)4(OH)8·4H2O; Red Coral: Corallium rubrum (organic gemstone)

Turquoise: Hardness 5-6, sky blue to green, waxy to subvitreous luster, triclinic. Red Coral: Hardness 3-4, vivid red/orange, calcium carbonate composition, dull luster when raw to high polish.

Identified March 22, 2026More mineral →

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Physical properties

Turquoise: Hardness 5-6, sky blue to green, waxy to subvitreous luster, triclinic. Red Coral: Hardness 3-4, vivid red/orange, calcium carbonate composition, dull luster when raw to high polish.

Formation & geological history

Turquoise forms via hydrothermal processes in aluminum-rich rock near copper deposits. Red Coral is an organic gemstone formed by marine polyps in deep, dark seawater environments, typically in the Mediterranean Sea.

Uses & applications

Predominantly used in jewelry (rings, necklaces, bracelets) and ornamental carvings. They are staple materials in Native American (especially Navajo and Zuni) jewelry styles.

Geological facts

Turquoise is one of the oldest known gemstones, used by Ancient Egyptians and Persians. Red Coral is considered a 'biological gemstone' rather than a mineral, as it is produced by living organisms.

Field identification & locations

Identify Turquoise by its opaque blue-green color and potential brown/black matrix; check for 'reconstitution' or dyed magnesite clones. Identify Coral by its unique growth patterns and lack of reaction to heat (plastic melts). Historically significant in Southwestern US and Tibetan cultures.

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