Hessonite is a mineral with a hardness of 8 out of 10 on the Mohs scale of mineral hardness [?]. These Cubicly structured gems are made of calcium aluminum silicate, their full chemical compound being Ca3Al2(SiO4)3.

Hessonite is the brown-orange variety of Grossular, a nesosilicate in the Garnet group, with an isometric crystal system.

It appears with dodecahedral or trapezohedral crystals, cinnamon-brown to orange because of its iron content. Its color matches that of the oil of cinnamon. It also appears as golden-yellow, yellow-brown, or reddish-brown.

It is very hard, heavy, fragile, has no cleavage. It is transparent to translucent with vitreous luster, infusible, and insoluble. Under artificial light it becomes fiery red, and contains small inclusions that appear as rounded oily streaks or swirls known as treacle. Recent examinations show that this is the result of a mosaic structure caused by intergrown hessonite grains.

Scapolite inclusions have been reported in massive hessonite from Maligawila (Sri Lanka), and also from Lelatema (Tanzania). Lamellar growth structures in Mexican hessonite produce iridescent colours similar to that reported for Mexican andradite.

Yellow-orange hessonite shows no spectrum in lighter tones; however, with increasing colour saturation, absorption towards the blue end of the spectrum becomes more intense.

Hessonite is a mineral typical of regional and contact metamorphism of calcareous rocks, associated with calcite, wollastonite, vesuvianite, diopside, and scapolite.

Superb, clear hessonite crystals are found in the gem-bearing sands of Sri Lanka, India, in the rodingite bodies of California (Ramona), the western Alps (Val d'Ala, Val d'Aosta and Valle del Sangone, in Val della Gava, Liguria-all in Italy), at Asbestos (Canada), Mali, Namibia, Tanzania, Mexico, Brazil, and Maharitra (Madagascar). Lighter oranges, yellows and peachy-coloured stones occur in deposits in Alberta and Quebec (Canada).

It is also called "cinnamon stone," "essonite," "cinnamite," "kaneelstein" (German)

It can be confused with spessartite and hyacinth.

Some misnomers for hessonite include: California hyacinth - hessonite from California (USA); Ceylon hyacinth - hessonite garnet from Sri Lanka; Oriental hyacinth; false hyacinth.

Why is Hessonite called Gomed in ancient texts?

In Sanskrit and ancient Indian texts, Hessonite is known as Gomed or Gomedha due to its color resembling cow's fat or flesh. It holds significant importance in Vedic astrology as the gem representing Rahu.

What causes the unique treacle-like appearance?

Hessonite's distinctive swirled or roiled internal appearance, often called treacly, comes from high refractive index and characteristic inclusions. This internal pattern helps distinguish it from other orange gems.

Are Sri Lankan Hessonites better than others?

Sri Lankan (Ceylon) Hessonites are considered premium due to their ideal honey-to-cinnamon color and exceptional clarity. Other notable sources include India and Tanzania, but Sri Lankan material often commands higher prices.

How to spot fake Hessonite?

Real Hessonite shows distinctive swirled inclusions, high refractive index, and single refraction. Look for natural color zoning and specific gravity of 3.65. Glass imitations lack these characteristics and internal patterns.

Why do Hessonite colors vary so much?

Color ranges from golden yellow to deep reddish-orange based on iron and manganese content. The most valued show a pure cinnamon-orange color without brown tones. Variations can appear more yellow or red.

Is Hessonite treatment common?

Unlike many gems, Hessonite is rarely treated. Its natural color is stable and treatments uncommon. Most market specimens are completely natural, which adds to their value for collectors and traditional use.

What size Hessonite is most valuable?

Unlike some gems, Hessonite remains attractive in larger sizes. Clean stones over 5 carats with ideal color can command premium prices. Size matters less than color intensity and clarity in determining value.

The specific gravity [?] for Hessonite is 3.65, its refractive index [?] is 1.73-1.75, and its double refraction [?] is None.

History

Hessonite derives its name from the Greek "hesson," meaning "less" or "inferior," referring to its lower density and hardness compared to other varieties of garnet.

Industrial Usages

Hessonite is often lower-priced than the higher-quality and more popular spessartite garnet, and thus can often be difficult to find on the market.