Howlite

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Not well known to the general public, howlite is one of those minerals that is almost more famous for imitating another mineral. In this case, the other mineral is turquoise, a phosphate gemstone. Howlite is naturally milky white in color and often has dark vein-like mineral inclusions. Because of its porosity, it accepts dye fairly easily, achieving a turquoise-like blue color. Howlite accepts a nice polish and its porcelain-like luster is appealing.

Howlite Polished
Howlite Classification
Common Name Howlite
Species Howlite
Howlite Optical Properties
Transparency Semitranslucent - Opaque
Refractive Index 1.586-1.605
Tolerance:(+0.003/-0.003)
Birefringence 0.019
Optic Character Biaxial
Optic Sign Negative
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: inert to weak bluish white or orange
LWUV: Inert to moderate bluish white or orange
CCF Reaction Dyed blue: pink to red
Pleochroism None
Howlite Characteristic Physical Properties
Hardness 3-3.5
Streak White
Specific Gravity 2.450-2.710 Typical:2.580
Toughness Varies
Inclusions Howlite is often dyed to look like turquoise or lapis lazuli. The stones frequently have a dark gray or black spider web matrix.
Luster Vitreous
Stability Poor
Fracture Granular
Cleavage None
Howlite Chemistry & Crystallography
Chemical Formula Ca2B5SiO9(OH)5
Crystal System Monoclinic
Chemistry Classification Borate

Howlite Colors

  • Blue Howlite Blue
  • White Howlite White

Alternate Names

Howlithe, Turquenite, Dyed Howlite

Countries of Origin

United States of America (the); Unknown; China; Mexico; South Africa

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Tim Matthews

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Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.