Howlite
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| Howlite | |
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| General | |
| Category | Mineral |
| Chemical formula | Ca2B5SiO9(OH)5 |
| Identification | |
| Color | white/gray/black |
| Crystal habit | nodules |
| Crystal system | monoclinic |
| Cleavage | absent |
| Fracture | conchoidal, uneven |
| Mohs Scale hardness | 3.5 |
| Luster | vitreous to dull |
| Refractive index | opaque to translucent |
| Streak | gray to black |
| Specific gravity | 2.5+ |
Howlite, a calcium borosilicate hydroxide (Ca2B5SiO9(OH)5), is a silicate found in evaporite deposites. [1] Howlite was discovered at Tick Canyon, California in 1868 by Henry How (1828 - 1879), a Canadian chemist, geologist, and mineralogist.
In appearance, it is white with fine grey or black veins in an erratic, often web-like pattern, and is opaque with a sub-vitreous lustre. Its structure is monoclinic with a Mohs hardness of 3.5 and lacks regular cleavage.
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Howlite is commonly used to make decorative objects such as small carvings or jewelry components. Because of its porous texture, howlite can be easily dyed to imitate other minerals, especially turquoise because of the superficial similarity of the veining patterns. Howlite is also sold in its natural state, sometimes under the misleading trade names of "white turquoise" or "white buffalo turquoise", or the derived name "white buffalo stone".
[edit] References
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