Howlite, a calcium borosilicate hydroxide, is a beautiful snow white opaque color with gray markings stone that is often dyed to represent Turquoise. It is usually found in compact earthy masses and very rarely in crystals found in evaporate deposits.
Howlite was discovered near Windsor, Nova Scotia in 1868 by Henry How (1828–1879), a Canadian chemist, geologist, and mineralogist. How was alerted to the unknown mineral by miners in a gypsum quarry, who found it to be a nuisance. He called the new mineral silico-boro-calcite; it was given the name Howlite by James Dwight Dana.