Seylan Gems & Jewelry
“Garnet” is a group name. Almandine, pyrope, spessartine, grossular, and andradite can all be sold under it, and they do not share one refractive index or one density. A careful listing says which look you are buying, not only the group name.
Specifications
Typical published ranges used in gemology. Specific gravity below matches our carat calculator default where applicable. (SG 3.70)
| Hardness (Mohs) | About 6.5–7.5, depending on the species |
|---|---|
| Refractive index | Roughly 1.73–1.89 across the group; one number does not fit all |
| Optic character | Singly refractive as a group |
| Specific gravity | Commonly about 3.5–4.3; our calculator default is 3.70 and is only a starting estimate |
| Chemistry | A silicate group; the metal in the formula (iron, magnesium, manganese, calcium) changes the species |
| Lustre | Vitreous to subadamantine |
Red is the color people expect, and it can be almandine, pyrope, or a mix. Orange spessartine, green grossular, and color-change stones are still garnet. Do not assume two red garnets are the same species because they look alike in a thumbnail.
Garnet is singly refractive, which separates it from ruby. It is also usually free of the strong doubling you see in zircon. Those are useful checks. They still do not replace a stated species on a listing when the price depends on it.
Because density varies inside the group, a carat estimate from millimetres is rougher for garnet than for sapphire. If our calculator and the stated weight disagree by a wide margin, treat that as a question to ask, not as proof the listing is wrong. Proportions, a mixed species, or a measurement taken at the girdle can all move the estimate.
Hardness is high enough for careful jewelry wear, but it is not corundum. A point or a thin girdle can chip. Look at the photo of the edge, not only the face.
We describe the color and the measurements we have. If a stone is a named variety, that name belongs in the title because it changes what you are comparing. Ask us if you need the species spelled out before you buy. This page is shopper education. It is not a report on any one stone.
Ready to look
Browse certified stones estimate carat from millimetres or ask us to help interpret a report.
Join collectors who shop certified Ceylon stones with real 360° views. Code emailed instantly.
No spam. Unsubscribe anytime. One code per customer.
Enter your email. If you leave, we will send this cart back — Ceylon gems often sell as unique pieces.
Sapphire
Ruby
Alexandrite
Emerald
Padparadscha
Aquamarine
Spinel
Garnet
Peridot
Tourmaline
Tanzanite
Citrine
Quartz
Chrysoberyl
Apatite
Topaz
Amethyst
Lolite
Zircon
Sinhalite
Cats Eye
Opal