Howlite | Gemopedia

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.
Alternate
Names
Howlithe, Turquenite, Dyed Howlite
Colors
White, Often With Dark Gray, Black Spider Web Matrix; Commonly Dyed Most Often To Imitate Turquoise, Lapis, Coral, Rhodonite

Howlite Classification

Common Name

Howlite

Species

Howlite

Variety

Colors

White, Often With Dark Gray, Black Spider Web Matrix; Commonly Dyed Most Often To Imitate Turquoise, Lapis, Coral, Rhodonite

Alternate Names

Howlithe, Turquenite, Dyed Howlite

Gemstone Groups

Key Separations

appearance, RI, SW fluorescence and SG

Comments

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

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

Dispersion

Comments

Howlite Chemistry & Crystallography

Chemical Name

Chemical Formula

Ca2B5SiO9(OH)5

Synthesis

Crystal System

Monoclinic

Classification

Borate

Nature

Natural

Crystallinity

Crystalline to Aggregate

Comments

Howlite Characteristic Physical Properties

Hardness

3-3.5

Streak

White

Specific Gravity

2.45-2.71 Typical:2.58

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

Comments

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