Sphene | Gemopedia

A brilliantly transparent gem, sphene has fire greater than that of diamond! This gem is named from the Greek word for "wedge," as its crystals are typically wedge shaped, but may be referred to by its mineral name, titanite. On rare instances, sphene may be pink, brown or black in color, but is mainly found in a range of green to yellowish green colors. Another characteristic sphene possesses is birefringence, or double refraction, meaning that light splits into two rays as it passes through the gem. As a result, the back facets appear as double images, giving the gem a soft, hazy appearance, similar to the doubling seen in zircon.
Alternate
Names
Titanite, Chrome Sphene
Colors
Yellow, Green, Brown, Orange, Red

Sphene Classification

Common Name

Sphene

Species

Sphene

Variety

Colors

Yellow, Green, Brown, Orange, Red

Alternate Names

Titanite, Chrome Sphene

Gemstone Groups

Key Separations

OTL RI reading, very strong eye visible doubling, possibly spectra

Comments

Chrome sphene is intense green in color.

Sphene Optical Properties

Transparency

Transparent - Translucent

Refractive Index

Over The Limit 1.9-2.034
Tolerance:(+0.020/-0.020)

Birefringence

0.1-0.135

Optic Character

Biaxial

Optic Sign

Positive

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: Inert
LWUV: Inert

CCF Reaction

Pleochroism

Trichroic, (in green gems) strong greenish yellow, yellow to brown, and colorless; (in brown gems) strong yellow, reddish-orange, and brownish yellow and brownish orange, (in yellow gems) moderate to strong greenish yellow, brownish-orange, and colorless

Dispersion

Strength: strong fire Value: 0.051

Comments

Sphene Chemistry & Crystallography

Chemical Name

calcium titanium silicate

Chemical Formula

CaTiSiO5

Synthesis

Crystal System

Monoclinic

Classification

Silicate

Nature

Natural

Crystallinity

Crystalline

Comments

Sphene Characteristic Physical Properties

Hardness

5-5.5

Streak

White

Specific Gravity

3.5-3.54 Typical:3.52

Toughness

Varies

Inclusions

Sphene occasionally contain tiny crystals that aline in straight rows or "feathers", natural inclusions, actinolite needles and twinning is common. Stones have strong dispersion and eye-visible doubling.

Luster

SubAdamantine

Stability

Fracture

Conchoidal, Splintery

Cleavage

Good, in one direction

Comments

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