Sinhalite

Pale yellow to yellow-brown, transparent, often mistaken for peridot or tourmaline

Pale Yellow Yellow-Brown

Optical properties

Optical characteristics

Ref. index: 1.668 – 1.707
Birefringence: 0.039
Luster: Vitreous
Pleochroism: Strong Strong trichroism: pale brown, brownish-green, and greenish-yellow depending on crystal axis.
Fluorescence: Inert to weak.

Origins

Source localities

Sri Lanka Sri Lanka: Ratnapura / Elahera

Premium ★ Top Source

Classic Ceylon source for sapphire and many alluvial gems; known for bright colors and good clarity.

70% est. supply

Myanmar Myanmar: Mogok Valley

Premium ★ Top Source

Classic source for ruby, sapphire, spinel and other collector gems.

30% est. supply

Inclusions

Inclusions & features

Crystals Crystal Inclusions Under 10x loupe: solid, well-formed mineral crystals trapped inside the host gem. They may… Zoning Color Zoning Under 10x loupe in immersion: bands or patches of deeper or lighter color arranged… Fractures Fingerprint Inclusions Under 10x loupe: curved or wavy lines of tiny dots forming patterns that look…

Identification

Instruments used

Refractometer Measures refractive index, the backbone of gem identification Dichroscope Reveals pleochroism, instantly eliminates singly-refractive stones Polariscope Determines single vs. double refraction, quick and conclusive Hydrostatic Scale Measures specific gravity, works even on opaque stones 10x Loupe Your most-used instrument, start every examination here Spectroscope Reads characteristic absorption lines, confirms chromium, iron, copper

Specifications

Hardness: 6.5 – 7 Mohs
Ref. index: 1.668 – 1.707
Sp. gravity: 3.48 – 3.5
Birefringence: 0.039
Crystal system: Orthorhombic
Luster: Vitreous
Species: Sinhalite

Market price $ 150 – 2,000 / ct

Rarity Collector Grade

Sinhalite is extremely rare in faceted form; most known faceted specimens are of museum or advanced collector quality.

Confused with

Peridot Peridot has strong birefringence and visible doubling of back facets.
Dravite Brown tourmaline (dravite) has different RI range and growth tubes.
Hessonite Hessonite garnet is singly refractive with characteristic 'treacle' internal texture.

Expert tip

Sinhalite was only formally recognized as a distinct mineral species in 1952; it was long confused with brown peridot from Sri Lanka. The strong trichroism with three distinct colors (pale brown / brownish-green / greenish-yellow) is the key identifier.