mineral

Howlite (Tumbled)

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Hardness: 3.5 on Mohs scale; Color: White to milky grey with black or dark grey veining; Luster: Sub-vitreous to dull; Crystal structure: Monoclinic; Cleavage: None (conchoidal fracture); Specific Gravity: 2.45 - 2.58.

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

Identified March 24, 2026More mineral →

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Physical properties

Formation & geological history

Howlite is an evaporite mineral, typically found in continental evaporite deposits. It forms as nodules in silty clays and marls, often associated with other borate minerals. Most major deposits date from the Cenozoic era.

Uses & applications

Used primarily for decorative objects, lapidary work, and inexpensive jewelry. Due to its porous nature, it is frequently dyed blue to imitate turquoise or red to imitate coral.

Geological facts

First discovered in 1868 near Windsor, Nova Scotia, by Canadian geologist Henry How. In its natural form, it is often called 'white turquoise' or 'cwhite buffalo stone' by New Age practitioners, though it is unrelated to turquoise.

Field identification & locations

To identify in the field, look for cauliflower-like nodules; it is much softer than quartz. It is commonly found in Nova Scotia (Canada), California (USA), and parts of Turkey and Germany. Pieces are easily identified by the distinct spider-web veining.

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