Source: Brazil and many gemstone producing areas connected to pegmatite dikes (see Colored Gemstones 101 for more information on pegmatite dikes)

Chemical: K(LiAl)3(SiAl)4O10(F,OH)2

Crystal System: Monoclinic but normally occurs in flat tabular crystal formations in connection to gemstone crystals such as tourmaline and spodumene.

Formation: Mainly pegmatite dikes and igneous rocks



Unusual Properties: Has perfect cleavage separation as shown in photograph at left. The top layer of this specimen as a break at the cleave plane. And color separations can be seen at the other levels of cleave plane. This mineral is very often seen with excellent crystals of tourmaline in the Brazilian pegmatite dikes.