Astrophyllite | Gemopedia

Astrophyllite is golden-yellow to dark brown and usually forms as bladed crystals radiating from a common center. It gets its name from the Greek astron, meaning "star", and phyllon, meaning "leaf." It may also be translated as "star sheets," fitting because of the interwoven star shapes that the crystals sometimes form and because of its strange luster, which can be metallic in some crystals and pearly in others. Although there are occurrences of astrophyllite around the world, some of the finest crystals come from remote mountainous regions in arctic northern Russia.
Colors
Brown, Reddish Brown, Golden Yellow, Bronze Like

Astrophyllite Classification

Common Name

Astrophyllite

Species

Astrophyllite

Variety

Colors

Brown, Reddish Brown, Golden Yellow, Bronze Like

Alternate Names

Gemstone Groups

Key Separations

RI, optic character and appearance

Comments

Astrophyllite Optical Properties

Transparency

Translucent - Opaque

Refractive Index

1.678-1.758

Birefringence

Optic Character

Biaxial

Optic Sign

Positive

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV:
LWUV:

CCF Reaction

Pleochroism

Trichroic, orangy red, orangy yellow, yellow

Dispersion

Strength: strong fire

Comments

Astrophyllite Chemistry & Crystallography

Chemical Name

potassium sodium iron manganese titanium silicate hydroxide

Chemical Formula

(K,Na)3(Fe2+,Mn)7Ti2Si8O24(O,OH)7

Synthesis

Crystal System

Triclinic

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline to Aggregate

Comments

Astrophyllite Characteristic Physical Properties

Hardness

3

Streak

Golden

Specific Gravity

3.2-3.4

Toughness

Poor

Inclusions

The stone is composed of star or leaf like sheets some of which can have a metallic or pearly luster.

Luster

Greasy

Stability

Fracture

Uneven

Cleavage

Perfect, in one direction, Poor, in one direction

Comments

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