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
Transparence 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 group: Pyralspite Series
Garnet Group: Ungradite Series

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