GARNET

Garnets occur naturally in a wide range of colours and this is due to their chemical complexity.
The common varieties are:
Pyrope, a Magnesium Aluminium Silicate, usually pale red to deep red in colour
Almandine, an Iron Aluminium Silicate, red to very dark red in colour.
Spessartine (or Spessartite),  a Manganese Aluminium Silicate, commonly found in orange to red shades.
Grossular, a Calcium Aluminium Silicate with colours ranging from the green sub-variety Tsavorite to brown and orange stones.
Andradite, a Calcium Iron Silicate with high lustre and dispersion with a range of colours from green Demantiod to yellow/brown Topazolite and black Melanite.
Other varieties include colour-change Pyrope and Hydrogrossular Garnet.