Howlite
HowliteJewelryWiki Editorial·2 sources·Reviewed 2026-08-04
A chalky white stone with grey veining, and the most successful imposter in the gem trade: dyed blue, it is sold as turquoise. The veining even mimics turquoise’s matrix. At Mohs 3–3½ it is roughly a third as scratch-resistant as the turquoise it imitates, and IGS lists dyeing as its ONE typical treatment.
Properties
| Property | Value | Authority |
|---|---|---|
| Mohs hardness | 3–3½ [1] | — |
| Specific gravity | 2.45–2.58 [1] | — |
| Chemical formula | Ca2B5SiO9(OH)5 [2] | — |
| Crystal system | Monoclinic [2] | — |
| Common treatments | Dyeing — the only treatment IGS lists for it, and the reason most people have handled howlite without knowing. Blue "turquoise" beads at a low price are very often dyed howlite. That is not fraud if disclosed, and it is fraud if it is not. [1] | — |
| Suitability for daily wear | Poor. At Mohs 3–3½ it is softer than a copper coin and will scratch against almost anything, including the quartz dust in ordinary household air. [1] | — |
| Care cautions | Keep away from acetone, alcohol and prolonged sunlight, all of which can lift or fade dye. Never use an ultrasonic cleaner. [1] | — |
Sources
- International Gem Society — gemstone articles — International Gem Society (IGS, gemstone information articles (gemsociety.org))
- Handbook of Mineralogy — Mineral Data Publishing / Mineralogical Society of America (Handbook of Mineralogy, Mineral Data Publishing)