Because all garnets are isotropic and essentially identical in thin section, this is where you’ll find garnet images, GigaPans, and videos. If you’re looking for the characteristics of specific garnets, please refer to their individual pages.
Broadly speaking, you’ve got your reddish garnets and your non-reddish garnets. The reddish garnets are pyralspites, a compound abbreviation of pyrope, almandine, and spessartine. The non-reddish garnets are ugrandites, a compound abbreviation of uvarovite, grossular, and andradite. (Note that the uvarovite and andradite links will take you to mindat.org; only pyrope, almandine, spessartine, and grossular are covered here.)
Physical Properties |
|
| Chemical formula | All garnets have chemistries
A3B2Si3O12 For the chemistries of specific garnets, refer to |
| Class | Nesosilicate Isolated tetrahedra |
| Crystal system | Cubic |
| Habit | Dodecahedral Trapezohedral Usually euhedral to subhedral |
| Color | Red (pyrope) Deep red (almandine) Pink (spessartine) Violet (spessartine) Brown (grossular, andradite) Yellow (grossular, andradite) Green (grossular, andradite) Emerald green (uvarovite only) Occasionally black (pyrope only) |
| Hardness | 6.5-7.5 |
| Specific gravity | 3.54-4.19 |
| Cleavage | None |
| Fracture | Subconchoidal to conchoidal |
| Luster | Resinous |
| Transparency | Transparent to translucent |
| Streak | White |
Optical Properties |
|
| PPL | High relief Colorless or pale May look mottled gray |
| XPL | Isotropic |
| δ | None |
| after Perkins, 337-340 |
Garnet in Hand Sample
Garnet in garnet schist
Garnet in uncut garnet schist
Garnet in Archean-aged basement rock from Montana
Glorious almandine porphyroblasts in a schist from Alaska
Small garnets in the Castner Marble of West Texas
Small garnet hand sample
Garnet in granite
Garnet-bearing anorthosite
Garnetiferous metagraywacke
Garnet in the Maidens gneiss of Virginia’s Goochland Terrane (the thin section in the GigaPans below is Maidens gneiss)
Garnet in blueschist after eclogite
Garnet in 3D
Thin Section GigaPans
Garnet mica schist in plane polars
Garnet mica schist in crossed polars
Garnet in the Maidens Gneiss of Virginia’s Goochland Terrane, plane polars
Garnet in the Maidens Gneiss of Virginia’s Goochland Terrane, crossed polars
Sillimanite-garnet gneiss, plane polars
Sillimanite-garnet gneiss, crossed polars
