Pink Sapphire
Last updated: April 2026
Pink sapphire is chromium-colored corundum with insufficient saturation to qualify as ruby — the ruby/pink sapphire boundary is defined by dominant hue. Myanmar (Mogok) material often shows strong red LW fluorescence. Sri Lankan pink sapphires are pastel and highly valued. Easily confused with rubellite tourmaline, morganite, spinel, kunzite, and pink topaz — all separated by RI, SG, and optic character. Beryllium diffusion has created significant amounts of orange-pink treated material in trade.
Pink Sapphire has a specific gravity of 4.00 and a refractive index of 1.762–1.770, with a Mohs hardness of 9. It is uniaxial −.
Physical & Optical Properties
Measured with a polariscope, a refractometer, a hydrostatic balance, a Chelsea filter, a UV torch, a loupe, a darkfield loupe and a spectroscope — step-by-step for each.
Through the refractometer
Drawn from the refractive index above, on a 1.40–1.81 scale. How to take this reading.
Related: Corundum Varieties
Key Differentiators
- Strong red LW fluorescence (especially Myanmar material) — stronger than rubellite
- Hardness 9 — harder than all pink simulants
- Uniaxial negative — vs. biaxial kunzite/morganite/topaz; much higher RI than all pink uniaxial simulants
- RI 1.762 — much higher than morganite (1.583) and spinel (1.718)
- Strong dichroism (pink/orange-pink) — direction-dependent under dichroscope
Natural vs. Synthetic
Synthetic pink sapphire is commercially available (Flame fusion (Verneuil), Flux (Chatham, Kashan), Hydrothermal, and others). Distinguishing natural from synthetic typically requires microscopic examination of internal features.
- Microscopy — inclusions: Natural pink sapphire: rutile silk (often fine and abundant in unheated material), zircon crystals with strain halos, fingerprint inclusions, angular/hexagonal color zoning. Unheated stones typically have intact silk. Synthetic: Flame fusion: curved growth striae and gas bubbles (diagnostic). Flux: wispy flux veils and platinum platelets. Hydrothermal: nail-head spicules, seed plate. Czochralski: nearly flawless.
- UV Fluorescence (LW): Natural pink sapphire: often strong red LW, especially Myanmar; Sri Lankan may be moderate; iron-rich stones weaker. Fluorescence typically zoned or patchy. Synthetic: Synthetic: may show strong uniform red (flame fusion/Czochralski) or variable (flux). Overly uniform, chalky-strong red with SW equal to LW intensity is suspicious for synthetic.
- Chelsea Filter: Chromium-bearing natural pink sapphires often react orange-red to red. Iron-bearing or low-Cr stones are inert. Synthetic: High-purity synthetic pink corundum (high Cr, no Fe) often shows strong red Chelsea reaction — stronger than most naturals of equivalent color.
Loupewise Pro includes a two-phase natural vs. synthetic testing protocol for Pink Sapphire.
Common Simulants
- Rubellite Tourmaline: Rubellite: uniaxial negative, strong dichroism (red/orange-red/pale), RI 1.624–1.644, SG 3.06 — much lower than pink sapphire. Chelsea filter typically inert.
- Morganite (Pink Beryl): Morganite: uniaxial negative but RI 1.577–1.583 and SG 2.72 — substantially lower than pink sapphire on both. Weaker dichroism.
- Pink Spinel: Pink spinel: isotropic (SR, no dichroism), RI ~1.718, SG ~3.60 — lower than pink sapphire. Strong red LW fluorescence in some pink spinels. Chelsea filter reaction varies.
- Kunzite (pink spodumene): Kunzite: biaxial positive, RI 1.660–1.676, SG 3.18, very strong dichroism/trichroism (pink/colorless/violet), perfect cleavage — easily distinguished by cleavage and biaxial character.
- Pink topaz: Pink topaz: biaxial, RI 1.609–1.643, SG 3.53, perfect basal cleavage — lower RI and SG than pink sapphire, cleavage is a strong separator.
Treatments
- Heat Treatment
- Beryllium (Lattice) Diffusion
- Glass/Resin Fracture Filling
- Irradiation
Related Comparisons
Measurement Guides
Identifying a pink sapphire? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Pink Sapphire is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
Practice exams →