mineral

Howlite

Calcium borosilicate hydroxide (Ca2B5SiO9(OH)5)

AI-generated identification · may be incorrect

Hardness: 3.5 on Mohs scale; Color: White to milky grey with black or dark brown veining; Luster: Sub-vitreous to earthy; Crystal Structure: Monoclinic; Cleavage: None (conchoidal fracture)

Hardness: 3
Color: White to milky grey with black or dark brown veining
Luster: Sub-vitreous to earthy

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 3.5 on Mohs scale; Color: White to milky grey with black or dark brown veining; Luster: Sub-vitreous to earthy; Crystal Structure: Monoclinic; Cleavage: None (conchoidal fracture)

Formation & geological history

Formed in evaporite deposits in arid environments through the precipitation of boron-rich waters into sedimentary beds. Often found in nodules or cauliflower-like masses.

Uses & applications

Commonly used as a gemstone for jewelry, beads, and carvings. It is also a significant industrial source of boron. Due to its porous nature, it is frequently dyed blue to imitate turquoise.

Geological facts

Named after Henry How, a 19th-century Canadian mineralogist who first described it in Nova Scotia. It is often referred to as 'White Turquoise' or 'Buffalo Turquoise' in the jewelry market, although it is unrelated to actual turquoise.

Field identification & locations

Identified by its white porcelain-like appearance and distinctive erratic grey veining. It is relatively soft and can be scratched by a copper coin. Commonly found in California, USA, and Nova Scotia, Canada.