Turquoise

Turquoise, a captivating gemstone with a name that pays homage to its origins, derives from the French word "turquois," meaning "Turkish stone." Composed of hydrated copper and aluminium phosphate, turquoise showcases a distinctive blue-green hue that has been cherished for centuries.

Geologically, turquoise forms in arid regions where water interacts with copper deposits, leading to the creation of this enchanting gemstone. Notable sources include the United States, Mexico, and Iran, each offering unique shades and qualities.

What distinguishes turquoise is its vivid colour, often associated with the vibrant landscapes of the American Southwest. This gemstone has a rich history, revered by ancient cultures for its protective and healing properties.

One interesting fact about turquoise is its role as a symbol of friendship and good fortune. It is often used in jewellery and amulets to bestow positive energy and blessings upon the wearer. With its captivating hue and cultural significance, turquoise remains a cherished gemstone worldwide.

Click on the terms in the table below to discover their meaning

Image of tumbled Turquoise — Tumbled Turquoise

Image of Sleeping Beauty Turquoise earrings — Sleeping Beauty Turquoise earrings by Christina Rutz (used under CC BY 2.0 licence)

Image of Turquoise Mosaic Mask Carved in Volcanic Stone from the city of Teotihuacan, Mexico — Turquoise Mosaic Mask Carved in Volcanic Stone from the city of Teotihuacan, Mexico by Gary Todd (used under CC0 1.0 licence)

Click on the terms in the table below to discover their meaning

Name	Turquoise
Category	Phosphate mineral
Chemical Formula	CuAl₆(PO₄)₄(OH)₈ · 4H₂O
Chemical Formula
IMA Symbol	Tqu
Crystal System	Triclinic
Crystal Habit	Rare steep pinacoidal crystals; fine granular to cryptocrystalline, nodular to globular crusts, veinlets, massive
Twinning	Common
Cleavage	Perfect / Good
Fracture	Conchoidal
Tenacity	Brittle
Hardness (Moh's Scale)	5 - 6
Specific Gravity	2.86 - 2.91
Diaphaneity	Transparent in crystals; translucent to opaque if massive
Colour	Turquoise, blue, blue-green, green
Streak	White to pale greenish blue
Lustre	Vitreous in crystals; dull to waxy if massive
Optical Class	Biaxial (+)
Refractive index	nα = 1.61
	nβ = 1.62
	nγ = 1.65
Birefringence	δ = 0.040
Dispersion	Rd = 0.014
Pleochroism	X = colourless; Z = pale blue or pale green


Clarity	Has own grading system based on colour, texture, and the absence of matrix
Notable Varieties	Sleeping Beauty Turquoise, Persian Turquoise, Bisbee Turquoise, Kingman Turquoise, Morenci Turquoise, Chinese Turquoise, Royston Turquoise, Cerrillos Turquoise, Pilot Mountain Turquoise, Mexican Turquoise

References

Gemological Institute of America. (2023). Turquoise. Retrieved from: https://www.gia.edu/turquoise

Hudson Institute of Mineralogy. (2023). Turquoise. Retrieved from Mindat.org: https://www.mindat.org/min-4060.html

Mineralogical Society of America. (2005). Turquoise. In J. W. Anthony, R. A. Bideaux, K. W. Bladh, & M. C. Nichols (Eds.), Handbook of Mineralogy. Chantilly, VA 20151-1110, USA: Mineralogical Society of America. Retrieved from https://www.handbookofmineralogy.org/pdfs/turquoise.pdf

About the Author

Daniel Gillespie is student of Web Development and the developer of Gemology 101. With a straightforward and informative approach, Daniel invites readers to explore the world of gemology, offering a valuable resource for both enthusiasts and those seeking knowledge about precious stones.