Key properties
| Chemical formula | Ca3Al2(SiO4)3 |
| Crystal system | Cubic |
| Mohs hardness | 7-7.5 |
| Toughness | Fair to good |
| Refractive index | 1.730-1.740 |
| Optic character | SR (singly refractive; isotropic) - anomalous double refraction occasionally visible |
| Dispersion | 0.0280 |
| Specific gravity | 3.60-3.68 |
| Cleavage | None; parting sometimes seen |
| Fracture | Conchoidal to uneven |
| Habit | Usually irregular grains and nodules ('potatoes') in graphitic rocks - euhedral crystals are rare |
| Lustre | Vitreous, sometimes greasy; polish: Vitreous |
| UV fluorescence | Inert |
| Pleochroism | None (isotropic) |
| Cause of colour | Vanadium with a trace of chromium substituting in the grossular lattice (V3+/Cr3+) |
| Typical inclusions | Graphite flakes • diopside • apatite • quartz • fluid films and fingerprints - clean stones are common but the rough is often fractured |
| Stability | Stable to light and normal chemicals; slightly attacked by hydrofluoric acid |
| Heat sensitivity | Abrupt temperature change can fracture stones; no heat treatment is used on tsavorite |
| Care and cleaning | Ultrasonic usually safe, risky if visibly fractured • steamer never • warm soapy water safe |
| Birthstones | January (garnet) |
| Availability | Limited - fine clean material over a few carats is genuinely rare; small melee more available |
| Recognition | Recognised among coloured-stone enthusiasts and promoted heavily since the 1970s, but still unfamiliar to many consumers |
Varieties
Tsavorite
| Colour | light to dark green to strongly yellowish green; finest is a saturated 'grass' green |
| Transparency | transparent |
| Clarity type | Type II - typically included; eye-clean stones common because heavily included rough is cut around |
| Phenomena | None |
| Appearance | A crisp, lively green - from spring green to deep forest - with a brightness emerald rarely matches because tsavorite is usually cut cleaner and brilliance is higher. |
| Trade names | tsavolite (rare spelling variant) |
| Misnomers | occasionally sold as 'green garnet' without variety name; historical attempts to market it as an emerald substitute |
| Typical sizes | Melee to about 3 ct is the workhorse range; clean stones over 5 ct are rare; the largest faceted examples include a 325 ct stone (2006) and the 116.76 ct 'Lion of Merelani' (Smithsonian) |
| Cutting styles | Faceted in all standard shapes; emerald cuts and cushions show saturated colour best; calibre melee for pavé |
| Key separations | vs demantoid: demantoid RI 1.888, higher dispersion, 'horsetail' chrysotile inclusions; tsavorite RI ~1.74, graphite inclusions • vs chrome diopside: diopside DR, RI 1.675-1.701, much softer (5.5-6.5), strong green but sleepy • vs emerald: emerald RI 1.577-1.583, DR, typically heavily included (Type III) • vs green tourmaline: tourmaline DR, RI 1.62-1.64, strong dichroism • vs peridot: peridot RI 1.65-1.69, 'lily pad' inclusions, yellowish green cast |
| Sources (localities) | Kenya (Tsavo region, Taita-Taveta) • Tanzania (Merelani/Lelatema hills) • Madagascar • Pakistan (minor) |
| Availability | Limited; supply is sporadic because mining is small-scale and host-rock pockets are unpredictable |
| Market notes | Discovered by Campbell Bridges in Tanzania (1967) and Kenya (1971); named by Tiffany president Henry Platt after Tsavo East National Park and launched in 1974. Prices rise steeply above two carats and steeply again above five. |
| Care notes | Protect from hard knocks - rough often carries pre-existing fractures; avoid steamers |
| In short | Tsavorite is East Africa's vanadium-green grossular garnet, bright, clean and untreated. Fine saturated stones over five carats are rare enough to be museum pieces. |
| Size (ct) | USD per carat | Tier | As of |
|---|---|---|---|
| 0.50–1.00 | $200.00 – $800.00 | good to fine | 2026-10-26 |
| 1.00–3.00 | $500.00 – $2500.00 | fine | 2026-10-26 |
| 3.00–10.00 | $1500.00 – $6000.00 | fine to museum | 2026-10-26 |
Retail market survey, per carat unless noted. Ranges describe what commercial to fine stones trade at; exceptional stones and provenance premiums sit above them.
Sources
GIA gem encyclopedia · mindat.org · Wikipedia
Data compiled and fact-checked against gemmological literature, October 2026 (JDMIS gem reference). Properties are ranges accepted in gemmological practice; individual stones vary.
See also
Gemstone reference entries: gem #71
Related materials: Almandine Garnet · Andradite Garnet · Grossular Garnet · Hydrogrossular Garnet · Pyrope Garnet · Rhodolite Garnet · Spessartine Garnet
Identification wizard · All 83 materials · Singapore gem labs