Howlite (Ca2B5SiO9(OH)5) is a calcium borosilicate hydroxide. It is usually white, often with veins of other minerals running through the nodules. When dyed with a blue color, it resembles turquoise, and is often referred to as turquenite. Howlite is found in quantity in California, especially Death Valley and San Bernardino County. Other localities include Canada, Mexico, Germany, Russia, and Turkey.
Howlite was named in 1868 after Canadian chemist Henry How who discovered it in Tick Canyon, California.