Specimens Carletonite is a rare silicate mineral that is found in only one location. It comes from the classic mineral locality of Mont Saint-Hilaire , Quebec, Canada.
Crystals show good tetragonal prismatic form and can have a bright sapphire blue color.
The darker blue crystals can demonstrate excellent pleochroism. Pleochroism is a condition in which the color of the crystal will change depending on the angle at which it is viewed. Carletonite varies from blue to white. Other pleochroic minerals include elbaite , spodumene , zoisite and cordierite . Some crystals have been cut as gems, but these are mostly for collectors as carletonite has low hardness and good cleavage.