Mint Garnet Identification Guide
How to identify Mint Garnet, a light minty-green grossular garnet, by its color, single refraction, hardness, and lack of cleavage.
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What Mint Garnet Looks Like
Mint Garnet is a trade name for light, fresh green grossular garnet (closely related to tsavorite but paler and more pastel). Its color is a soft minty to slightly yellowish green. Fine material is transparent and brilliant.
- Color: Light mint-green to yellowish-green.
- Luster: Vitreous, bright when faceted.
- Transparency: Transparent to translucent.
- Habit/form: Rounded dodecahedral/trapezohedral grains and crystals; often cut as faceted gems.
Step-by-Step Field ID Checklist
- Assess the color: A delicate, pastel green — lighter than emerald, "minty."
- Look for crystal form in rough: Garnets form well-rounded 12- or 24-sided crystals with no flat cleavage faces.
- Check for single refraction: Garnet is isotropic — under a polariscope it stays dark (no doubling). In a loupe you will not see doubled back facets (rules out tourmaline/peridot).
- Note inclusions: Often clean; may have fingerprint or needle inclusions.
- Run hardness and density tests below.
Key Diagnostic Tests
- Mohs hardness: ~7–7.5 — scratches glass readily.
- Streak: White.
- Cleavage: None; conchoidal to uneven fracture (a key garnet trait).
- Density: ~3.5–3.7 g/cm3 (grossular) — heavy, sinks fast in heavy liquids.
- Acid: No reaction.
- Optics: Singly refractive (isotropic); refractive index ~1.73–1.75.
Common Look-Alikes and How to Tell Them Apart
- Tsavorite garnet: Same species (grossular) but a deeper, more saturated green; mint garnet is paler. Often a marketing distinction.
- Peridot: Doubly refractive (you see doubled facet edges through a loupe), softer (6.5–7), and more yellow-olive; garnet is singly refractive.
- Green tourmaline: Doubly refractive, lower density (~3.0–3.1), shows strong pleochroism; garnet shows none.
- Demantoid garnet: Andradite, with much higher dispersion ("fire") and "horsetail" inclusions; mint garnet is grossular with lower fire.
- Green glass: Often has gas bubbles, lower hardness/density, and may be singly refractive too — check for bubbles and softer hardness.
- Chrome diopside: Softer (5.5–6.5), doubly refractive, darker green.
Where It Is Found
Mint and tsavorite-type grossular garnets come mainly from East Africa — Kenya, Tanzania (Merelani), and Madagascar — in metamorphic graphitic gneiss and calc-silicate rocks.
Frequently asked questions
How can you tell if Mint Garnet is real?
Genuine mint garnet is singly refractive (no doubled facets), has no cleavage, rates ~7–7.5 hardness, and is heavy (density ~3.5–3.7). Gas bubbles, lower hardness, or visible facet doubling point to glass or a different gem.
What is the difference between mint garnet and tsavorite?
Both are green grossular garnet; tsavorite is a deeper, more saturated green, while mint garnet is a lighter, pastel minty green. The distinction is largely about color saturation.
Mint garnet vs peridot — how do you tell them apart?
Peridot is doubly refractive (you see doubled back facet edges through a loupe) and softer, while mint garnet is singly refractive with no doubling and is harder and denser.
What does mint garnet look like?
It is a bright, transparent, soft mint-to-yellowish-green gem with a glassy luster, typically cut into clean faceted stones.