mineral
Howlite
Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)
AI-generated identification · may be incorrectHardness: 3.5 on Mohs scale; Color: White to milky grey with dark grey or black veins; Luster: Sub-vitreous to earthy; Crystal structure: Monoclinic; Cleavage: None; Specific gravity: 2.53-2.59
- Hardness
- 3
- Color
- White to milky grey with dark grey or black veins
- Luster
- Sub-vitreous to earthy
Identified More mineral →
Explore Howlite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5 on Mohs scale; Color: White to milky grey with dark grey or black veins; Luster: Sub-vitreous to earthy; Crystal structure: Monoclinic; Cleavage: None; Specific gravity: 2.53-2.59
Formation & geological history
Formed in evaporite deposits as a result of the precipitation of boron and calcium from saline water in arid environments. Often found in cauliflower-like nodules.
Uses & applications
Primarily used for decorative carvings, lapidary work, and beads. Highly valued as a base material for dyeing to imitate turquoise or lapis lazuli due to its porous nature.
Geological facts
Named after Henry How, a 19th-century Canadian mineralogist who first described it in Nova Scotia. It is often sold under the trade names White Turquoise or White Buffalo, though it is chemically distinct from turquoise.
Field identification & locations
Identified by its signature grey spider-web veining on a white background and low hardness (can be scratched by a copper coin). Found primarily in Canada (Nova Scotia) and the USA (California).
