Top 10 Varieties Of the Gemstone TourmalineMetal_Treasure Tourmaline is most commonly black but it can occur in almost all colors and even in bi-colored or multi-colored crystals. That's a very interesting gem.
Tourmaline's hardness on Mohs scale is 7-7.5 /10 (not the best but still good).
The Top Ten
It's a very rare neon-bright blue gem. Paraiba tourmaline was named for the Brazilian state of Paraiba where it was discovered. - Metal_Treasure
Its crystals may be green at one end and pink at the other, and even with other colors between these two. - Metal_Treasure
Its name comes from the word 'indigo' - Metal_Treasure
Its name (Rubellite) comes from ruby - because it's red like ruby - Metal_Treasure
That's one of the most interesting crystals - green on the outside and pink inside - Metal_Treasure
It's dark yellow to brownish black - Metal_Treasure
It's black and is the most common variety of tourmaline that may account for 95% or more of all tourmaline in nature. - Metal_Treasure
It is an uncommon form of Tourmaline that forms different crystal formations than the most of the other Tourmalines. Its name comes from Uva Province, Sri Lanka, where it was first identified. - Metal_Treasure