Is tsavorite a garnet?
Tsavorite is green grossular garnet, Ca3Al2(SiO4)3: hardness 6.5 to 7, index 1.743 (IGS). Why demantoid, uvarovite, YAG and emerald are not tsavorite.
Yes. GIA and the International Gem Society both call tsavorite a green variety of grossular, the calcium aluminium garnet Ca3Al2(SiO4)3, and it has no IMA row of its own. Lualenyi tsavorite reads 1.743 and SG 3.61. It stays grossular while aluminium outnumbers vanadium: worked, 0.14 V per formula is 2.31% V2O3, and goldmanite begins near 15.80%.
In short
- The definition. GIA’s garnet quality factors say both tsavorite and hessonite are varieties of grossular, and that tsavorites are green. The International Gem Society calls tsavorite an emerald-green variety of grossular garnet. Grew et al., American Mineralogist 98 (2013), the IMA garnet report, decodes tsavorite, tsavolite and tsavolith as grossular.
- Not a species name. The September 2026 IMA-CNMNC Master List lists grossular, Ca3Al2(SiO4)3, A, 1962 s.p.; a whole-line scan finds 0 lines containing tsavo. The species page is grossular; its hydrogarnet line and Y-site ladder are not repeated here.
- The goldmanite line. Grew et al. name a garnet by the dominant constituent at each site. Their tsavorite example, from Bordage et al. (2010), holds 0.14 vanadium per formula unit: 7% of the Y site, 2.31% V2O3 by mass, worked. The name would change to goldmanite where vanadium outnumbers aluminium, 1.00 V and 15.80% V2O3 in an aluminium–vanadium garnet. The goldmanite sheet’s Sandy mine analysis has 1.20 V and prints 18.3% V2O3.
- The green-garnet window. Tsavorite reads 1.743 (gem society) and grossular 1.734 (sheet). Goldmanite (1.821), uvarovite (1.865) and andradite (1.887) read higher on their sheets, as does YAG at 1.833 (gem society). Emerald (1.577 to 1.583) and peridot (1.65 to 1.69) read lower and twice, on GIA’s figures.
- Where the window fails, documented. Mali garnet, a grossular–andradite blend on the gem society’s account, reads 1.77 in most stones, between the windows. By weight the green garnets crowd together: tsavorite 14.46 g in water for 20.00 g, goldmanite 14.65 g, uvarovite 14.69 g, andradite 14.74 g, gaps of 0.19 to 0.28 g. And grossular may show anomalous birefringence, so a polariscope does not always read it as singly refractive.
| Name | What it is (source) | IMA row? | Vanadium at Y | Refractive index; readings | 20.00 g piece in water |
|---|---|---|---|---|---|
| Tsavorite | Green grossular (GIA; IGS); grossular (Grew, Appendix 2) | No; grossular is | 0.14 pfu, 7% of Y: 2.31% V2O3 (Bordage, via Grew; worked) | 1.743 (IGS, Lualenyi); one | 3.61; 14.46 g |
| Grossular, Handbook sheet | Ca3Al2(SiO4)3 | Yes: A, 1962 s.p. | 0 (ideal) | 1.734; one, weak strain birefringence | 3.594; 14.44 g |
| The goldmanite line | V equals Al at Y; grossular below, goldmanite above (dominant constituent, Grew) | - | 1.00 pfu, 50%: 15.80% V2O3 (worked) | - | - |
| Goldmanite, Sandy mine (sheet) | V-dominant garnet, Ca3V3+2(SiO4)3 on the IMA list | Yes: A, 1963-003 | 1.20 pfu, 60%; 18.3% V2O3 printed | 1.821 (sheet); one | 3.74 to 3.77; 14.65 to 14.69 g |
| Uvarovite, Handbook sheet | Cr at Y; Ca3Cr2(SiO4)3 | Yes: A, 1967 s.p. | Not applicable | 1.865; one, weak strain anisotropism | 3.77 to 3.81; 14.69 to 14.75 g |
| Demantoid | Green variety of andradite (GIA) | No; andradite is | Not applicable | 1.881 to 1.888 (IGS); andradite sheet 1.887 | 3.82 to 3.88 (IGS): 14.76 to 14.85 g; sheet 3.8 to 3.9: 14.74 to 14.87 g |
| Mali garnet | Grossular–andradite blend, predominantly grossular (IGS) | No | Not stated | 1.77 in most (IGS) | Not given |
| YAG | Synthetic yttrium aluminium garnet, isostructural with garnet (Grew); a tsavorite simulant (IGS) | No | None | 1.833 (IGS); one | 4.55 (IGS): 15.60 g |
| Emerald | Green variety of beryl (GIA) | No; beryl is | None | 1.577 to 1.583 (GIA); two | 2.72 (GIA): 12.65 g |
| Peridot | Gem variety of olivine (GIA) | No | None | 1.65 to 1.69 (GIA); two | 3.34 (GIA): 14.01 g |
Is tsavorite a garnet? The definition in one sentence
Tsavorite is green grossular: a garnet, of the calcium aluminium species Ca3Al2(SiO4)3, sold under a variety name. GIA’s garnet quality factors say gemmologists and dealers subdivide some garnet species into varieties by colour, that both tsavorite and hessonite are varieties of grossular, and that tsavorites are green. The International Gem Society tsavorite article calls it an emerald-green variety of grossular garnet and writes its formula Ca3Al2Si3O12 plus vanadium and chromium.
The IMA test, by script. The September 2026 IMA-CNMNC Master List has a grossular row, Ca3Al2(SiO4)3, status A, 1962 s.p., Russia, and no row for tsavorite or tsavolite; a case-insensitive scan finds 0 lines containing tsavo. In Grew et al., American Mineralogist 98 (2013), Appendix 2, the list of synonyms, obsolete, varietal and discredited garnet names, decodes all three spellings, tsavorite, tsavolite and tsavolith, as grossular. A label reading tsavorite (grossular) carries both names.
What the species sheet adds. The Handbook grossular sheet gives cubic crystals, hardness 6.5 to 7, density 3.594 and n = 1.734, and lists yellow-green and pale to dark green among its colours. It does not use the word tsavorite. The rest of grossular’s record is on grossular.
When does tsavorite stop being grossular? The goldmanite line
The goldmanite line: a green calcium garnet is grossular while aluminium outnumbers vanadium at the Y site, and goldmanite once vanadium outnumbers aluminium. Grew et al. state that species designation is based on the dominant constituent at a given crystallographic site, extended by the dominant-valency rule; aluminium and trivalent vanadium share a valence, so the larger of the two names the garnet. The IMA list carries goldmanite as Ca3V3+2(SiO4)3, A, 1963-003, USA.
Worked. Grew et al. cite Bordage et al. (2010) on a grossular of the tsavorite variety containing 0.14 V per formula unit, all of it trivalent. As Ca3(Al1.86V0.14)Si3O12 that is a formula mass of 453.79 and 2.31% V2O3, with vanadium on 7% of the Y site: 14% of the way to the line. At the line, Ca3(AlV)Si3O12, the figure is 15.80%, and pure goldmanite is 30.07%. The goldmanite sheet’s Sandy mine, New Mexico analysis prints 18.3% V2O3 with V 1.20, Al 0.47 and Fe 0.33 at Y: vanadium-dominant, and named goldmanite.
What the line does not decide. It needs an analysis; a refractometer or a balance cannot place a stone on it. The goldmanite sheet’s n of 1.821 and density of 3.74 to 3.77 belong to a vanadium-dominant analysis, and this page does not interpolate a vanadium content from an index. Colour causes for tsavorite are not given here.
What tsavorite is not: demantoid, uvarovite, YAG and emerald
Demantoid is the other green garnet, and it is andradite, not grossular. GIA says demantoid is a brilliant green variety of andradite, and Grew et al. decode demantoid as andradite. The International Gem Society gives demantoid 1.881 to 1.888 and SG 3.82 to 3.88; the andradite sheet prints 1.887 and 3.8 to 3.9. Tsavorite at 1.743 is at least 0.138 lower. The species is on andradite and its classification on is andradite a garnet.
Uvarovite is the chromium garnet. The IMA list has it as Ca3Cr2(SiO4)3; its sheet prints n = 1.865 and density 3.77 to 3.81, 14.69 to 14.75 g in water for 20.00 g. The International Gem Society says a trace of chromium may produce a chrome spectrum in green grossular varieties; a garnet stays grossular until chromium, like vanadium, outnumbers aluminium. The species page is uvarovite.
YAG has the garnet structure but is not a mineral. Grew et al. describe yttrium aluminium garnet, {Y3}[Al2](Al3)O12, among synthetic rare-earth compounds isostructural with garnet, and a script over the IMA list finds no row with that formula. The International Gem Society lists green glass and green YAG as tsavorite simulants and gives YAG 1.833, SG 4.55 and hardness 8.5: 15.60 g in water, 1.14 g above tsavorite. Emerald is the green variety of beryl on GIA’s emerald facts, 1.577 to 1.583 with two readings; peridot is olivine on GIA’s peridot facts, 1.65 to 1.69. Neither is a garnet; see is olivine the same as peridot.
When the answer changes: Mali garnet, strain and the scale
Mali garnet sits between grossular and andradite, and which it is depends on an analysis. The International Gem Society calls Mali garnet a blend of grossular and andradite, predominantly grossular, with an index of 1.77 in most specimens: 0.013 above hessonite’s highest and 0.095 below uvarovite. Grew et al. decode Mali garnet and grandite as grossular-andradite. A green garnet reading near 1.77 may be grossular or andradite by the dominant-constituent rule, and this page does not interpolate one from the other.
Single refraction is not always clean. The grossular sheet prints weak strain birefringence, and the International Gem Society says tsavorite is isotropic but may show anomalous birefringence. A polariscope that blinks on a green garnet does not make it a non-garnet; the one-reading test on the refractometer is the firmer check, and the general method is on how to tell if garnet is real, whose 1.71 line is not repeated here.
The balance is weak among green garnets. Worked as 20 − 20/D for 20.00 g: tsavorite 14.46 g, grossular 14.44 g, goldmanite 14.65 to 14.69 g, uvarovite 14.69 to 14.75 g, andradite 14.74 to 14.87 g. The gaps are 0.19 to 0.28 g, small enough that a mounted or included stone can blur them; emerald, at 12.65 g, is 1.81 g lighter. The method is on how to measure specific gravity at home.
Why is it called tsavorite? Name and localities
Named for Tsavo, first found in Tanzania. The International Gem Society says tsavorite is named after Tsavo East National Park in Kenya, was first discovered in Tanzania in 1967, and is sometimes called tsavolite. GIA says Campbell Bridges mined tsavorite in Kenya near Tsavo National Park, and Grew et al.’s Appendix 2 attributes the name tsavorite to Campbell R. Bridges and Henry B. Platt.
Against the sheet. The grossular sheet’s Distribution names gems from the Merelani Hills, southeast of Arusha, Tanzania, and the Taita Hills, near Voi, Kenya. It does not say which variety either produced, and we do not add a variety to either. The gem society’s Lualenyi, Kenya figures, 1.743 and 3.61, are the ones used on this page; its other countries are not on the sheet and are not added.
The other grossular variety, orange to brownish red, is on is hessonite a garnet. The classification questions are indexed at the collecting guides. This page gives no buying advice. Nothing on this site is offered for sale; the wanted list is the only commercial route.