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Corundum · Variety of Ruby

Star Ruby

Red to purplish-red with six-rayed asterism

Pink Red
Optical properties

Optical characteristics

Ref. index
1.762 – 1.77
Birefringence
0.008 – 0.01
Luster
Vitreous to silky (cabochon)
Pleochroism
Strong: red / orangy-red
Fluorescence
Strong red (LW)
Origins

Source localities

Myanmar Myanmar: Mogok Valley
Legendary ★ Top Source

Classic Burmese star rubies show strong six-rayed stars with vivid red body color; the most prestigious star ruby origin.

20% est. supply
Sri Lanka Sri Lanka: Ratnapura / Elahera
Premium ★ Top Source

Sri Lanka (Ceylon) produces classic star rubies with strong asterism and transparent to translucent body.

15% est. supply
Mozambique Mozambique: Montepuez / Alto Ligonha / Cuamba
Notable

Mozambique produces star rubies alongside its dominant facet-grade material from Montepuez.

20% est. supply
Thailand Thailand: Chanthaburi / Kanchanaburi
Commercial

Thailand produces star rubies, typically darker with brownish-red tones.

12% est. supply
Madagascar Madagascar: Ilakaka / Andranondambo region
Notable

Madagascar produces star rubies from the Andilamena and Vatomandry regions with variable quality.

8% est. supply
India India: Rajasthan / Odisha / Karnataka
Commercial

India is a major source of star ruby, often large with strong asterism but typically purplish-red body color.

25% est. supply
Treatments

Enhancement & treatment

Heat Heat Treatment, Corundum Heat is the most common corundum treatment. It can improve color and clarity, but… Diffusion Surface Diffusion Surface diffusion adds coloring elements near the surface. It is less durable than body…
Inclusions

Inclusions & features

Needles Silk, Rutile Needles Under 10x loupe: extremely fine bright lines crossing in three directions at 60° angles.… Zoning Color Zoning Under 10x loupe in immersion: bands or patches of deeper or lighter color arranged…
Identification

Instruments used

10x Loupe Your most-used instrument, start every examination here High CRI Penlight Tiny concentrated white spot for field checks, inclusions, fire, and fractures Fiber Optic Halogen Illuminator Intense pinpoint white light for inclusions, fractures, and treatment clues Refractometer Measures refractive index, the backbone of gem identification Hydrostatic Scale Measures specific gravity, works even on opaque stones