mineral

Howlite (Dyed to resemble Turquoise)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Hardness: 3.5 on Mohs scale; Color: Naturally white or grey with black/brown veining (dyed blue in this specimen); Luster: Sub-vitreous to earthy; Crystal Structure: Monoclinic; Cleavage: None (conchoidal fracture); Specific Gravity: 2.45-2.58

Hardness: 3
Luster: Sub-vitreous to earthy

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Howlite is an evaporite mineral found in nodular masses. It forms in continental evaporite basins where boron-rich fluids interact with clay or carbonate minerals. Most commercial deposits are from the Tertiary period.

Uses & applications

Primarily used as a decorative stone, for carvings, and in costume jewelry. Because it is highly porous, it is frequently dyed blue or green to imitate Turquoise (often called 'Turquenite') or red to imitate Coral.

Geological facts

Howlite was first discovered in Nova Scotia in 1868 by Henry How. In its natural white state, it is sometimes sold as 'White Turquoise' or 'White Buffalo Stone', although it is chemically unrelated to true Turquoise.

Field identification & locations

Identify in the field by its soft nature (it can be scratched by a copper coin, unlike real Turquoise which is harder) and characteristic 'web-like' grey veining. Common locations include Canada (Nova Scotia) and the USA (California and Nevada). Dyed versions often show deeper blue color concentrated in the cracks.

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