A variety of quartz

Hardness 7
Bluish purple to purple to reddish purple
Transparent to translucent

Care:
Ultrasonic: usually safe
Steamer: risky
Warm, soapy water: safe

Stability:
Heat: strong heat causes color to change or fade
Light: some stones may fade
Chemicals: senstitve to hydrofluoric acid and ammonium fluoride

Teatments:
Heating to improve color. Treatment is stable an not prevalent
Heat can also change amethyst to Citrine and Green Quartz.

Common sources:
Brazil, Uruguay, Namibia, Russia, US

Misnomers:
None known