Rock IdentifierTurquoise
Key takeaways
- Turquoise is a hydrated copper-aluminum phosphate, prized for sky-blue color.
- Much of it is porous and stabilized, dyed, or reconstituted; pure natural turquoise is scarce.
- Dyed howlite and magnesite are the classic cheap imitations.
What it is
Turquoise is a hydrated phosphate of copper and aluminum, colored blue by copper and greener where iron creeps in. It forms in arid, copper-rich regions and often shows a web of dark veins called matrix. It's opaque and fairly soft (5–6), which is why so much of it is treated to survive cutting.
The treatment spectrum
Very little turquoise is hard enough to use untreated. The market runs a spectrum: natural (untreated, rare and premium); stabilized (resin-infused to harden and deepen color — extremely common); dyed (color added); and reconstituted or 'block' (ground turquoise powder bonded with resin). Each step down is more affordable but less valuable, and honest sellers disclose which you're buying.
Imitations to know
The classic fakes are howlite and magnesite — naturally white, porous minerals dyed turquoise-blue, often with black 'matrix' drawn on. Dyed color tends to pool in cracks and can rub off with acetone; the base mineral is softer. Plastic and glass imitations feel warm and light. Genuine turquoise feels cool and stony, with more natural, irregular matrix.
Care & value
Turquoise is porous and can be discolored by oils, cosmetics, sweat, and sunlight — keep it clean and dry, and avoid ultrasonic cleaners. Value depends heavily on natural vs treated status and on even, vivid color; because imitation is rampant, provenance and disclosure carry real weight here.
