Etymology
The word garnet comes from the 14th‑century Middle English word gernet, meaning ‘dark red’. It is derived from the Latin granatus, from granum (‘grain, seed’). Due to the size, shape and color of some crystals similar to the fruit of “pomegranate” is likely that the name garnet has been inspired by this tree (Latin: “malum granatum”).
History
The first discovery dates to about 3100 B.C., in areas of the Middle East and Scandinavia. In the Bronze Age, this gemstone was very popular among craftsmen. At the time of the Crusades, the garnet was used to set armor and shields for the militia, it was considered that it granted protective powers to the ones that carried it. Some Asian and South American cultures used garnet by adding it to their bullets, considering that it increased the damage inflicted on their opponents. Garnet is one of the 12Th biblical and mythological stones, Jews and Christians said that a glowing red garnet, was responsible for pointing the way for Noah through the divine rage, during the flood myth.
Garnet Characteristics and Properties
| Mineral Type | Group IX Silicates (Nesosilicates) |
|---|---|
|
Color |
Red, champagne, pink, green, violet, orange, brown, yellow, black, blue |
|
Streak |
white |
|
Hardness |
6.5 - 7.5 Mohs |
|
Specific Gravity |
3.4 – 4.2 |
|
Cleavage |
Indistinct |
|
Fracture |
Conchoidal |
|
Crystal System |
Cubic |
|
Habit |
Dodecahedron, rhombic dodecahedron, trapezohedron, also in rounded grains and massive |
|
Chemical Formula |
X3 Y2 (SiO4)3
X+2 = Fe, Ca, Mn, Mg
Y+3 = Al, Fe, V, Ti, Cr |
|
Optical Properties |
Isotropic |
|
Transparency |
Transparent to opaque |
|
Luster |
Vitreous to resinous adamantine |
|
Refractive Index |
1.714 a 1.950 |
|
Birefringence |
None |
|
Pleochroism |
Non-pleochroic |
Uses
Garnet is a well-known gemstone and used in jewelry since ancient times (Egypt, Greece and Rome). It has been used by Jews and Christians as ornaments and cult objects and in the windows of cathedrals. At present, because it is considered the Gem of love, it is widely used in engagement rings. Thanks to its high hardness, the garnet is also used industrially as an abrasive and in the manufacture of sandpaper. In the field of crystal therapy, garnet is used for meditation, a highly energetic regenerative gem, purifying and used to improve social relations, open up to people in a positive way, it is the gemstone indicated to treat sadness and melancholia. It is also considered a powerful natural aphrodisiac, activator of sexual energy. Red garnets are considered the stones of love, blood and fury, flame and passion.
Garnet Varieties
Garnets are nesosilicates (silicate minerals) and are formed by tetrahedrons (SiO4) 3 isolates and joined together by cations (oxygen anions are not shared between tetrahedrons). When we refer to garnet, we really talk about the garnet group, since it is composed of several very similar mineral species, but when their consistent physical optical properties are reviewed and its chemical structure analyzed, you may notice some differences.
There are 6 garnet gemological species grouped into 2 series: 1) Pyralspite series; pyrope, almandine, and spessartine. 2) Ungradite series; grossular, andradite, uvarovite.
Garnet Structural Group
| Blythite | Mn32+Mn23+[SiO4]3 |
| Spessartine | Mn32+Al2(SiO4)3 |
| UM1984-37-SiO:CrMn | Mn32+(Cr3+,Mn3+)2Si3O12 |
| Khoharite | Mg3Fe23+(SiO4)3 |
| Knorringite | Mg3Cr2(SiO4)3 |
| Pyrope | Mg3Al2(SiO4)3 |
| Majorite | Mg3(Fe2+,Si,Al)2(SiO4)3 |
| Skiagite | Fe32+Fe23+[SiO4]3 |
| Almandine | Fe32+Al2(SiO4)3 |
| Kerimasite | Ca3Zr2(SiO4)(Fe3+O4)2 |
| Yafsoanite | Ca3Zn3(TeO6)2 |
| Goldmanite | Ca3V23+(SiO4)3 |
| Elbrusite | Ca3U6+ZrFe23+Fe2+O12 |
| Hutcheonite | Ca3Ti2(SiAl2)O12 |
| Irinarassite | Ca3Sn2Al2SiO12 |
| Toturite | Ca3Sn2(SiO4)(Fe3+O4)2 |
| Usturite | Ca3SbZr(Fe3+O4)3 |
| Dzhuluite | Ca3SbSnFe33+O12 |
| Bitikleite | Ca3SbSn(AlO4)3 |
| Andradite | Ca3Fe23+(SiO4)3 |
| Uvarovite | Ca3Cr2(SiO4)3 |
| Katoite | Ca3Al2(SiO4)3-x(OH)4x |
| Kimzeyite | Ca3(Zr,Ti)2((Si,Al,Fe3+)O4)3 |
| Schorlomite | Ca3(Ti,Fe3+)2((Si,Fe3+)O4)3 |
| Morimotoite | Ca3(Ti,Fe2+,Fe3+)2((Si,Fe3+)O4)3 |
| Henritermierite | Ca3(Mn3+,Al)2(SiO4)2(OH)4 |
| Schäferite | Ca2NaMg2(VO4)3 |
| Menzerite-(Y) | {(Y,REE),(Ca,Fe2+)}3{(Mg,Fe2+),(Fe3+,Al)}2[SiO4]3 |
| Berzeliite | (NaCa2)Mg2(AsO4)3 |
| Momoiite | (Mn2+,Ca)3V23+(SiO4)3 |
| Calderite | (Mn2+,Ca)3(Fe3+,Al)2(SiO4)3 |
| Palenzonaite | (Ca,Na)3CaMn22+(VO4)3 |
