The Composition and Color of Garnet Sand
Garnets are a group of silicate minerals that have been used as gemstones and abrasives since the Bronze Age.
All garnet species have similar physical characteristics and crystal shapes but differ in chemical composition. The various species are pyrope, almandine, spessartine, gross (hessonite or cinnamon-stone and tsavorite varieties), uvarovite, and andradite. Two solid solution series are made up of garnets: pyrope-almandine-spessartine and uvarovite-grossular-andradite.
Garnet is not a single mineral, but it describes several minerals that are closely related. Garnets are available in a variety of colors and have many types. However, Garnet gemstones’ most widely known color is dark red. When using the term “Garnet,” the dark red form is usually connotative; more descriptive gemstone terms are generally given to other color garnets.
Uvarovite: dark green.
Grossular: colorless, white, gray, yellow, green, green (various shades: pale green apple, medium green apple, dark green), brown, pink, reddish, black.
Andradite: Yellow-green, green, brown-green, yellow-orange, brown, black and black grayish. The color is associated with Ti and Mn’s content. The color is light if there is little of either element, and it may look grossly.
Pyrope: Purple red, pink-red, orange-red, raspberry, dark red. Note: Colorless pure pyrope; red colors are derived from Fe + Cr.
Almandine: red, brownish red, brownish-black, violet red.
Spessartine: red, reddish-orange, orange, yellow-brown, reddish-brown, blackish brown.
Malaysia: various shades of orange, red-orange, peach, and pink.
Rhodolite: usually has a distinctive purplish color.
There are two different groups and six different types. The two groups are Garnets of Calcium and Garnets of Magnesium.
- Almandine
- Pyrope
- Spessartite
- Grossular
- Andradite
- Uvarovite
It depends on the Garnet type, but it varies between 6.5 and 7.5 Mohs Hardness Scale
Garnet sand is an excellent abrasive and a common substitute in sandblasting for silica sand. For such blasting treatments, alluvial rounder garnet grains are more suitable. In water jets, the garnet is mixed with very high-pressure water to cut steel and other materials. Grants extracted from hard rock are ideal for water jet cutting as they are more angular in shape, hence more efficient in cutting.
