Hessonite — gomed, or "cinnamon stone" — is the Navratna stone of Rahu. It is a variety of grossular garnet coloured orange to brownish orange by iron and manganese, and it has a look that, once seen, is unmistakable: a roiled, swirly, heat-shimmer interior sometimes described as "treacle" or "scotch-in-water". That interior is the laboratory's best friend, because no imitation reproduces it.
What hessonite is
Grossular garnet (calcium aluminium silicate). Properties: RI about 1.73–1.75 (one reading — garnet is singly refractive), SG 3.60–3.68, hardness 7–7.5, no pleochroism, usually inert under UV, and the characteristic swirled internal texture with rounded crystal inclusions (commonly apatite and diopside). Colour ranges from honey yellow through orange to reddish brown.
What is sold as hessonite
Spessartine garnet. Also orange, also garnet, but a different species — manganese garnet — with a higher RI (1.79–1.81) and SG (4.1–4.2) and a different inclusion character. A fine stone in its own right, often more valuable than hessonite; sold as gomed by confusion or mislabelling.
Orange zircon. Doubly refractive with strong doubling visible under magnification; RI over the limit; SG 4.6–4.7; often shows the zircon absorption ladder. Very different on the bench.
Citrine and orange quartz. RI 1.54–1.55, SG 2.65, doubly refractive. Far lighter than garnet.
Orange glass. Singly refractive like garnet — which is why the polariscope alone does not separate it — but RI and SG differ, and glass shows bubbles and swirls of a manufactured kind, not the treacle texture.
Synthetic garnet-structure materials (YAG and others) in orange, and synthetic spinel. RI and SG off; no natural inclusions.
Andradite and other orange garnets. Separated by RI.
How the laboratory examines a claimed gomed
Polariscope: dark throughout (singly refractive) — eliminates zircon and quartz at once. Refractometer: about 1.74 confirms grossular; 1.80 points to spessartine. SG: 3.65 versus 4.15 supports the same distinction. Microscope: treacle texture and rounded inclusions confirm hessonite; bubbles indicate glass. Report states species and variety.
Treatments
Hessonite is essentially untreated in the trade. Heating is not used, dye is impractical in a transparent stone, and filling is uncommon. A report normally finds no indications of treatment. Coating has been reported occasionally.
Colour and quality
Preference varies: some traditions favour a lighter honey-orange, others a deep reddish brown. Clarity is judged with the understanding that the swirled texture is characteristic, not a flaw, though heavy cloudiness lowers the grade. All of this is opinion; identity is the finding.
Frequently asked questions
How can I tell hessonite from zircon?
Look through the stone at the far facet edges with a loupe: zircon shows doubled edges, hessonite does not. Zircon is also noticeably heavier for its size.
Is spessartine "better" than hessonite?
It is a different garnet, often more vivid and more valuable. Sold under its own name it is a fine stone. Sold as gomed it is a mislabelling; whether it "counts" for a tradition that specifies hessonite is for the wearer to decide.
Does hessonite need treatment disclosure?
Rarely, because it is rarely treated. A report still states what was examined.
Is the swirled interior a defect?
It is the identifying character of the stone. Strong swirls do not lower identity; only opacity or heavy clouding lowers the quality grade.
How is gomed weighed for astrological use?
The laboratory reports carats and grams; convert as needed. Ratti, carat and gram.