- Jewelry Identifier
- Gemstones
- Sapphire
* corundum gemstone
Sapphire: identification, value, and how to spot a fake
Same mineral as ruby (corundum); 'sapphire' refers to any color except red. Kashmir sapphires (cornflower blue, velvety) command extreme premiums. Padparadscha is the rare pink-orange variety.
Published May 30, 2026
Quick facts
- Mineral family
- corundum
- Chemical formula
- Al2O3 (Fe, Ti impurities)
- Mohs hardness
- 9
- Refractive index
- 1.762–1.77
- Specific gravity
- 3.97–4.05
- Crystal system
- trigonal
- Luster
- vitreous
- Dispersion
- 0.018
- Birthstone month
- September
Colors
Sapphire is found in blue, yellow, pink, orange, green, purple, colorless, padparadscha (pink-orange). The body color, its saturation, and how evenly it spreads through the stone are among the strongest drivers of value.
How to tell real from imitation
No single test settles it, but a few grounded checks quickly narrow things down for Sapphire. Hardness, brilliance, and the list of stones it is commonly confused with all give you something concrete to look for.
- Scratch resistance: genuine Sapphire sits at Mohs 9, so it should resist scratching from softer materials — a stone that mars far too easily is suspect.
- Brilliance & luster: Sapphire shows a vitreous luster and a refractive index of 1.762–1.77; imitations often look glassier or flatter under the same light.
- Density: a real Sapphire has a specific gravity near 3.97–4.05, so it feels heavier or lighter in the hand than many look-alikes of the same size.
- Commonly imitated by: blue spinel, blue topaz, iolite, tanzanite, synthetic sapphire. If a deal looks too good, suspect one of these substitutes first.
- Fast first read: photograph the stone in the Jewelry Identifier app to estimate the gemstone and its likely value range, then confirm anything important with a gemological lab.
Common treatments
- heat treatment (very common)
- diffusion (Be, Ti)
- lattice diffusion
Treatments are routine for many Sapphire stones, but they materially affect value and should always be disclosed — an untreated, lab-certified stone commands a clear premium over a treated one.
What to know about Sapphire
Same mineral as ruby (corundum); 'sapphire' refers to any color except red. Kashmir sapphires (cornflower blue, velvety) command extreme premiums. Padparadscha is the rare pink-orange variety.
Sources
* Frequently asked
FAQ
- Q. Is Sapphire hard enough for everyday rings?
- A. Yes. At a Mohs hardness of 9, Sapphire is durable enough for daily-wear rings; it resists the scratches that everyday surfaces inflict.
- Q. How can I tell Sapphire from blue spinel?
- A. Sapphire and blue spinel can look alike to the naked eye, but they differ in measurable properties — refractive index (1.762–1.77 for Sapphire), specific gravity (3.97–4.05), and hardness (Mohs 9). A gemologist confirms the distinction with a refractometer and loupe; the Jewelry Identifier app gives a fast first read from a photo.
- Q. Does Sapphire come in colors other than blue?
- A. Yes. Sapphire occurs in blue, yellow, pink, orange, green, purple, colorless, padparadscha (pink-orange). Color is driven by trace elements and treatment history, and it is one of the biggest factors in a stone's value.
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