Comparison · Minerals vs Organic Gems
Aragonite vs Red Coral
Aragonite and Red Coral are easy to confuse. Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Aragonite and Red Coral
- Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Aragonite is Transparent to translucent, Red Coral is opaque.
- They overlap in pink, but Aragonite also comes in clear, yellow, gray, and blue and Red Coral also comes in red, orange, and white.
- Well-formed crystals give it away: Aragonite is Orthorhombic, Red Coral is trigonal.
Aragonite vs Red Coral properties
| Property | Aragonite | Red Coral |
|---|---|---|
| Type | Minerals | Organic Gems |
| Mohs hardness | 3.5–4 | 3.5 |
| Luster | Vitreous to resinous | vitreous |
| Streak | White | White |
| Transparency | Transparent to translucent | opaque |
| Specific gravity | 2.93–2.95 | 2.65 |
| Crystal system | Orthorhombic | trigonal |
| Common colors | Colorless, White, Yellow, Gray, Blue, Pink | Red, Pink, Orange, White |
| Rarity | common | rare |
| Typical specimen value | $2–$150+ | $50–$3000+ |
Which is more valuable?
Red Coral is usually the more valuable of the two: a typical collector specimen runs about $300 against $20 for Aragonite, and premium Red Coral can reach $3000 or more.
About Aragonite
Aragonite is calcium carbonate, CaCO3, crystallizing in the orthorhombic system as a metastable polymorph of the more common mineral calcite. It readily forms in low-temperature settings such as caves, hot springs, and the shells of many marine organisms, and it slowly converts to calcite over geologic time. Twinned crystal clusters resembling six-rayed stars are among its most recognizable forms.
About Red Coral
Precious coral is formed from the skeletons of marine animals. Red coral from the Mediterranean has been prized for jewelry for thousands of years.
Aragonite vs Red Coral FAQ
Is Aragonite the same as Red Coral?
No. Aragonite is a mineral while Red Coral is a organic gem. Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Aragonite from Red Coral?
Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Aragonite is Transparent to translucent, Red Coral is opaque. They overlap in pink, but Aragonite also comes in clear, yellow, gray, and blue and Red Coral also comes in red, orange, and white.
Which is harder, Aragonite or Red Coral?
They are about equally hard, both near Mohs 3.5–4.
Which is more valuable, Aragonite or Red Coral?
Red Coral is usually the more valuable of the two: a typical collector specimen runs about $300 against $20 for Aragonite, and premium Red Coral can reach $3000 or more.
