|Chemical composition|| Ca3Al2(SiO4)3
Calcium aluminum silicate
Green, yellowish-green, yellow-orange and pastel.
Hessonite: granular internal structure from numerous crystal inclusions, giving it an oily appearance.
Green grossular: rod-like or needle-like crystals.
Hydrogrossular: granular structure often with irregular black inclusions.
Hessonite and green grossular: 1.73-1.76 (singly refractive)
Hydrogrossular garnet: 1.70-1.73 (singly refractive)
Grossular garnets sink in all common heavy liquids. Hydrogrossular garnet may sink slowly in methylene iodide.
Hessonite and green grossular garnet: 3.60-3.70
Hydrogrossular garnet: 3.35-3.55
Chelsea Colour Filter
Green stones may appear pinkish to red.
Hessonite is the brownish-red to yellowish-orange variety.
Green grossular garnet
Green grossular garnet is the bluish-green to yellowish-green variety. Within this group, Merelani Mint garnet is a grossular variety that is found in the Merelani Hills of Tanzania. It has emerged in the last few years with a bright pastel mint green color. Due to its limited availability it has remained mainly as a collector stone. The difference of it and Tsavorite is simply a matter of a lighter tone and saturation.
Hydrogrossular garnet is the green, pink, grayish-white to bluish variety of grossular.
Chrome grossular is a green variety of grossular.
Tsavorite (or tsavolite) is another green variety of chrome grossular.
Mali garnet is a yellow-green variety of grossular with a slight overlap in the grossular-andradite series.