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The mineral kyanite is an aluminium silicate of the sillimanite group (along with andalusite and sillimanite), also called alumino-silicate. It has the formula Al2O3Â·SiO2 (Al2SiO5). Its hardness varies widely depending on its crystallographic direction, from 5 to 7.5, and it has a specific gravity of 3.56-3.67. It is translucent, usually blue, but possibly white, gray, green, or black. It...
- A handkerchief.
- In general, any miraculous portrait of Christ.