What is Hessonite?
Hessonite is the honey to cinnamon-coloured variety of grossular garnet, known for warm colour and characteristic internal texture.
Mineralogy and structure
Reference formula: Ca3Al2(SiO4)3. Hessonite is a grossular variety, not an additional garnet species. Its warm colour and internal appearance are useful descriptive features, but composition and locality remain important. Hessonite belongs to the silicates and has a cubic crystal system. Typical hardness is 6.5–7 on the Mohs scale and specific gravity is approximately 3.5–3.7.
Colour and appearance
Typical colours include honey yellow, orange, cinnamon brown, reddish brown. The usual dodecahedral, granular, massive habit and vitreous, resinous lustre are useful descriptive features, but colour alone is not diagnostic.
Formation and localities
Hessonite forms in or is associated with calcium-rich skarns, contact-metamorphic rocks and metamorphosed limestones. Important documented localities include Sri Lanka, India, Tanzania, Kenya, Canada and Madagascar. A precise locality and host rock are more useful than a broad colour label.
Collecting notes
Hessonite should be labelled as a confirmed species, variety or group-level reference according to the evidence available for the specimen. Record colour, transparency, crystal form, matrix, locality and any treatment history.
