Hessonite Garnet

Orange to brownish red variety of grossular garnet, coloured by Fe3+-ions

Hessonit Hessonite Granat GarnetHessonit Hessonite Granat Garnet

Hessonite Shop

Origin of name: christened by French mineralogist René-Just Haüy after the Greek word hesson, meaning inferior. This garnet was also called (false) hyazinth and Haüy alluded to its inferior hardness, density and (at the time) value compared to true hyazinth, which is a trade name for orange and red zircon.

Synonyms and trade names: Cinnamon stone, false Hyazinth, Hyazinthoid, all antiquated

Can be confused with: other Garnets and orange or red gem stones like Zircon (Hyazinth), Citrin, Tourmaline etc.

Localities: Hessonite is rather common. Mindat.org lists 25 localities in Austria alone! However, gem quality Hessonite is rare and mostly comes from Sri Lanka. Other localities for gemmy material are in India, Myanmar (Burma), Russia and Canada.

Handling: Hessonite has no cleavage, is quite hard but it is also somewahat brittle. Set with care. hart aber auch etwas spröde. Vorsicht beim Fassen.

Worth knowing: apart from a plethora of rounded Apatite and/or Zircon crystals Hessonite often shows peculiar "treacly" streaks, often described as "heat wave pattern" or "oily".

Hessonite Shop

Gemmological Properties of Hessonite Garnet

Formula:
Ca3Al2[SiO4]3
Crystal system:
cubic
Mohs hardness:
6.5 - 7
Specific gravity:
3.594
Refractive index:
singly refractive, variable 1.731 to 1.748
Max. Birefringence:
may show weak strain birefringence up to 0.005
Lustre:
vitreous
Cleavage:
none
Fracture:
uneven to conchoidal, brittle
Colour:
orange to brownish red, rarely pure red