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Howlite
Current inventory:  0 gems
 

Chemistry:  Ca₂B₅SiO₉(OH)₅

Discovered in 1868;   IMA status: Valid (pre-IMA; Grandfathered).
Howlite is named after Henry How (1828-1879), Canadian chemist, geologist, and mineralogist, University of King's College, Windsor, Nova Scotia, Canada, who first described the species.

Classification

Mineral Classification:

Borates

Strunz 8th Ed. ID:

8/F.28-10

Nickel-Strunz 10th Ed. ID:

6.CB.20

6 : BORATES
C : Triborates
B : Ino-triborates

Related to:

None

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Crystals tabular, flattened, to 1 cm. Most commonly nodular. When massive, chalky to porcelaneous.

Twinning:

None

Physical Properties

Cleavage:

None

Fracture:

Even and Smooth in porcelaneous types

Tenacity:

Brittle

Moh's Hardness:

3.5

Density:

2.53 - 2.59 (g/cm³)

Radioactivity:

Not Radioactive

Optical Properties

Color:

White with Black veins in massive form; pale Brown translucent crystals

Transparency:

Usually Opaque, Translucent on thin edges

Luster:

Sub-Vitreous, Porcelaneous, Earthy

Refractive Index:

1.58 - 1.60  Biaxial ( - )

Birefringence:

0.0200

Dispersion:

None

Pleochroism:

None

Occurances

Geological Setting:

In borate deposits.

Common Associations:

Anhydrite, Bakerite, Colemanite, Gypsum, Ulexite

Type Locality:

Brookville, Windsor, Hants County, Nova Scotia, Canada

Year Discovered:

1868

View mineral photos:

Howlite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

In many cases, if the truth were known, Howlite would be better known as a Turquoise immitation. Howlite is frequently (and very convincingly) dyed blue to pass as Turquoise. It even contains gray to black threadlike impurities resembling the veining in Turquoise.

A current source of crystals is Cape Breton Island, Victoria County, Nova Scotia, Canada although these crystals are not suitable for faceting. The massive type can be found at the Sterling Borax Mine, Tick Canyon, Lang, Los Angeles County, California, USA (and a few other California locations); Magdalena, Sonora, Mexico; Susurluk, Turkey; Baljevac na Ibru, near Kraljevo, and near Bela Stena, Yugoslavia.
 

  
Howlite gems for sale:

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