Minerals ~ Garnet Group
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Hessonite Garnet. Jeffery Mine, Quebec, Canada. Bureau of Mines, Mineral Specimens C\01687.
Photo Credit: Public Domain
Garnet Group

Garnets (pronunciation: /ˈɡɑːrnət/) are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.
All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different species are pyrope, almandine, spessartine, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. The garnets make up two solid solution series: pyrope-almandine-spessartine and uvarovite-grossular-andradite.


Garnet species are found in many colors including red, orange, yellow, green, purple, brown, blue, black, pink, and colorless, with reddish shades most common.

Garnet species' light transmission properties can range from the gemstone-quality transparent specimens to the opaque varieties used for industrial purposes as abrasives. The mineral's luster is categorized as vitreous (glass-like) or resinous (amber-like).

Crystal structure

Garnets are nesosilicates having the general formula X3Y2(Si O4)3. The X site is usually occupied by divalent cations (Ca, Mg, Fe, Mn)2+ and the Y site by trivalent cations (Al, Fe, Cr)3+ in an octahedral/tetrahedral framework with [SiO4]4− occupying the tetrahedra.[4] Garnets are most often found in the dodecahedral crystal habit, but are also commonly found in the trapezohedron habit. (Note: the word "trapezohedron" as used here and in most mineral texts refers to the shape called a Deltoidal icositetrahedron in solid geometry.) They crystallize in the cubic system, having three axes that are all of equal length and perpendicular to each other. Garnets do not show cleavage, so when they fracture under stress, sharp irregular pieces are formed (conchoidal).


Because the chemical composition of garnet varies, the atomic bonds in some species are stronger than in others. As a result, this mineral group shows a range of hardness on the Mohs scale of about 6.5 to 7.5. The harder species like almandine are often used for abrasive purposes.

Magnetics used in garnet series identification

For gem identification purposes, a pick-up response to a strong neodymium magnet separates garnet from all other natural transparent gemstones commonly used in the jewelry trade. Magnetic susceptibility measurements in conjunction with refractive index can be used to distinguish garnet species and varieties, and determine the composition of garnets in terms of percentages of end-member species within an individual gem.[5]


ANDRADITE - Brown/Black Garnet
     Andradite is usually dark brown to black (melanite) and opague. Click on link to see our available listings

- Orange Garnet
     Hessonite is usually orange in color. Click on link to see our available listings

PYROPE - Red Garnet
Pyrope is usually red to dark red, the 'traditional garnet color.  Click on link to see our available listings

SPESSARTINE - Red Orange Garnet
     Spessartine is usually red orange in color and found with green Diopside crystals in Skarn. Click on link to see our
     available listings

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Mineral & Gemstone Chips in Mini Bottles

These little bottles contain top quality mineral and gemstone chips from our tailings. We high grade the material. Click on the image to see the full listing of available specimens

Price: Marked under Specimens


Mini bottles are created from left over chips from processing other mineral and gemstone specimens. We high grade the material so it is only available in limited quantities as we have available. In future we may seek to crush some material if there is sufficient interest in our bottles to warrant it.



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