ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Uneven
Not Available
Mg 3Al 6(Si,Al,B) 5O 21(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Ca 3B 6O 6(OH) 12 · 2H 2OAnthony et al , Handbook of Mineralogy (2001)