mineral

Howlite

Howlite (Calcium borosilicate hydroxide, Ca2B5SiO9(OH)5)

Hardness: 3.5 on Mohs scale; Color: White with grey or black veins; Luster: Sub-vitreous to pearly; Crystal structure: Monoclinic; Cleavage: None; Specific gravity: 2.53-2.59

Hardness: 3
Color: White with grey or black veins
Luster: Sub-vitreous to pearly

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 3.5 on Mohs scale; Color: White with grey or black veins; Luster: Sub-vitreous to pearly; Crystal structure: Monoclinic; Cleavage: None; Specific gravity: 2.53-2.59

Formation & geological history

Formed in evaporite deposits in arid environments, often associated with other calcium and boron minerals. It develops as nodules resembling cauliflower heads.

Uses & applications

Primarily used for decorative purposes, carvings, and as a semi-precious gemstone. Because it is porous, it is frequently dyed blue to imitate turquoise (sometimes called White Turquoise or Turquenite).

Geological facts

It was first discovered in 1868 by Henry How, a Canadian mineralogist, near Windsor, Nova Scotia. In its natural white state, it is often favored by those practicing crystal healing as a stone for calm and sleep.

Field identification & locations

Identify by its characteristic irregular grey veining (matrix) against a chalky white background. It is relatively soft and can be scratched by a steel knife, which helps distinguish it from more durable simulants like white jasper.

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