• One common use for garnet is as an abrasive.
• The mineral is crushed into tiny particles, glued up on a paper backing and turned into garnet paper, It is used for sanding.
• no streak
• vitreous luster
• transparent to opaque
• heavy, hard
• dark red colour turns to dull pink when weathered
• Another common use is for jewellery, but only if the garnet crystal is tansparent.

Massive Garnet in epidote (green)
Marmoraton Iron Mine, Marmoraton Township Ontario, CANADA

• This large, sandy, reddish-purple 12-sided garnet crystal weathered out of the mica schist it was in.
• The rain & the freeze/thaw cycle makes the schist break down because it is not hard.
• The garnet is very hard and so just rolls out of the schist into a pile of rock flakes & sand.
• The surface of the garnet gets dull because the water & chemicals of the sand corrodes its surface. This is called weathering.
• The crystal looks like a 12-sided die.

Left: Almandine Garnet Crystal
River Valley Occurrence, Dana Township,  Ontario  CANADA
Right: Almandine Garnet Crystal
Markstay, Ontario, CANADA

• COGWHEEL GARNETS are 2 garnets that have grown into each other. The faces that touch have angular "cogwheels".

Almandine Garnets in Mica Schist  
from Cormier Property, Lalonde Occurrence,
Markstay, Ontario  CANADA

Garnets   from Ecosource Mine, Kukagami Road, Sudbury
Ontario CANADA

Garnets   from Ambro Quarry
Marmorton Iron Mines, Marmora, Hastings County,
Ontario  CANADA

… well, some varieties may be taken for rubies when cut and polished, especially the pyropes and almandines.

Usually six are listed in the garnet group, the name changing with the elements present. Garnets belong to the isometric class of crystals which may suggest cubes (correctly), but garnet crystals look more like rough balls with their twelve sides – dodecahedrons. These forms are the most common but garnet can also be found massive and sometimes light coming through a thin edge may offer a clue. But more reliable field identification help is garnet’s higher-than-you’d expect S.G. of 3.53. Despite various chemical compositions the group is very hard at 7 to 7.5 and all have glass-like conchoidal fracture.

The garnet group belongs to the vast family of silicates, is widely distributed as an accessory mineral – i.e. small amounts – in many rocks but especially in strongly metamorphic types.

Here are some interesting but probably not helpful tips about garnet varieties:

• Grossularite – clear, green, yellow. A calcium (Ca) type
• Pyrope – deep red, black, a magnesium (Mg) type
• Almandite – deep red, brown, an iron (Fe) variety
• Spessartite – violet, brown, a manganese (Mn) variety
• Andradite – various greens, a calcium - iron type
• Uvarovite – emerald green, a calcium, chromium (Cr) type

Garnet is widely used as a gemstone and members of our own Brampton Club have turned out some fine "gems" of garnet.

But the big-time use of garnet is in the abrasives industry. A good choice too – it’s very hard, breaks with sharp edges and is common enough.