Amethyst vs Tanzanite

How Amethyst and Tanzanite differ in what they are, color, hardness and care.

Amethyst

	Amethyst	Tanzanite
What it is	Purple quartz, the February birthstone. Quartz is the second most abundant material in the Earth's crust.	The blue violet variety of the mineral zoisite, found only in Tanzania near Mount Kilimanjaro. It was discovered in 1967.
Birthstone for	February	December
Colors	Light pinkish violet to deep purple; Can look bluer or redder depending on the light	Pale blue to intense ultramarine with violet undertones; Shows different colors from different angles
Mohs hardness	7	6 to 7
Toughness	Good. Suitable for all jewelry, including rings, if you remember it scratches more easily than harder gems.	Fair to poor. It has cleavage and can break if struck.
Everyday wear	Good for everyday wear	Wear with care
Ultrasonic cleaner	Usually safe, except rare dyed or fracture filled stones	Never
Main sources	United States, Canada, Brazil, Zambia	Tanzania only (a few square miles near Mount Kilimanjaro)
Common treatments	Rarely dyed or fracture filled.	Routinely heat treated to turn brownish crystals blue or violet; this is stable.

Choose by the color you love and how the piece will be worn; for a ring worn every day, the tougher stone will last better.