Corundum · Variety of Sapphire
Parti Sapphire
Distinct two- or three-color zones of blue, green, and yellow within a single stone
Blue
Green
Yellow
Optical characteristics
- Ref. index
- 1.762 – 1.77
- Birefringence
- 0.008 – 0.01
- Luster
- Vitreous
- Pleochroism
- Strong Complex; multiple color zones each showing dichroism, creating an exceptional optical appearance at different angles.
- Fluorescence
- Inert.
Source localities
Sri Lanka
Sri Lanka: Ratnapura / Elahera
Notable
★ Top Source
Sri Lanka produces bicolor and parti-color sapphires from its alluvial deposits.
Tanzania
Tanzania: Umba Valley
Significant
Diverse alluvial deposit known for color-change sapphires, Umba padparadscha, rhodolite and malaia garnet.
Australia
Australia: New South Wales / Queensland fields
Commercial
Commercial sapphire and opal source; many darker blue to blue-green sapphires.
United States
USA: Montana sapphire fields
Major
★ Top Source
Known for Montana sapphires in blue, teal, green and fancy colors.
Enhancement & treatment
Inclusions & features
Zoning Color Zoning
Under 10x loupe in immersion: bands or patches of deeper or lighter color arranged…
Needles Silk, Rutile Needles
Under 10x loupe: extremely fine bright lines crossing in three directions at 60° angles.…
Fractures Fingerprint Inclusions
Under 10x loupe: curved or wavy lines of tiny dots forming patterns that look…
Fractures Feathers and Fractures
Under 10x loupe: irregular internal surfaces that catch light and appear bright, wing-like, or…
Crystals Crystal Inclusions
Under 10x loupe: solid, well-formed mineral crystals trapped inside the host gem. They may…
Instruments used
Refractometer
Measures refractive index, the backbone of gem identification
Dichroscope
Reveals pleochroism, instantly eliminates singly-refractive stones
10x Loupe
Your most-used instrument, start every examination here
UV Lamp, Long Wave and Short Wave
Fluorescence exposes treatments, synthetics, and origin
Polariscope
Determines single vs. double refraction, quick and conclusive