Comparison · Minerals
Beryl vs Corundum
Beryl and Corundum are easy to confuse because both are minerals. Corundum is harder (Mohs 9) than Beryl (Mohs 7.5–8), so Corundum will scratch Beryl and not the other way round. It scratches glass, steel and even quartz; only harder gems will mark it. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Beryl and Corundum
- Corundum is harder (Mohs 9) than Beryl (Mohs 7.5–8), so Corundum will scratch Beryl and not the other way round. It scratches glass, steel and even quartz; only harder gems will mark it.
- Streak color differs: Beryl leaves a white streak on unglazed porcelain, Corundum leaves white (colorless).
- Corundum feels noticeably heavier for its size (specific gravity 3.95–4.10 versus 2.63–2.92 for Beryl).
- They overlap in green, blue, pink, yellow, and clear, but Corundum also comes in red and gray.
- Well-formed crystals give it away: Beryl is Hexagonal, Corundum is Trigonal.
Beryl vs Corundum properties
| Property | Beryl | Corundum |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 7.5–8 | 9 |
| Luster | Vitreous | Adamantine to vitreous |
| Streak | White | White (colorless) |
| Transparency | Transparent to translucent | Transparent to translucent |
| Specific gravity | 2.63–2.92 | 3.95–4.10 |
| Crystal system | Hexagonal | Trigonal |
| Common colors | Green (emerald), Blue (aquamarine), Pink (morganite), Yellow (heliodor), Colorless (goshenite) | Red (ruby), Blue (sapphire), Colorless, Yellow, Green, Pink, Gray |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Beryl and Corundum trade in a similar range, around $20.
About Beryl
Beryl is a beryllium aluminum cyclosilicate, Be3Al2Si6O18, that crystallizes in the hexagonal system as six-sided prisms. Pure beryl is colorless, but trace elements produce a family of well-known gem varieties, including green emerald, blue-green aquamarine, and pink morganite. It typically forms in granite pegmatites, where slow cooling allows large, well-formed crystals to develop.
About Corundum
Corundum is aluminum oxide, Al2O3, crystallizing in the trigonal system and ranking as the second-hardest natural mineral after diamond. Its gem varieties, red ruby and every other color of sapphire, are colored by trace amounts of chromium, iron, or titanium substituting into an otherwise colorless crystal structure. Non-gem corundum is widely used as an industrial abrasive under the name emery.
Beryl vs Corundum FAQ
Is Beryl the same as Corundum?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Corundum is harder (Mohs 9) than Beryl (Mohs 7.5–8), so Corundum will scratch Beryl and not the other way round. It scratches glass, steel and even quartz; only harder gems will mark it.
How can you tell Beryl from Corundum?
Corundum is harder (Mohs 9) than Beryl (Mohs 7.5–8), so Corundum will scratch Beryl and not the other way round. It scratches glass, steel and even quartz; only harder gems will mark it. Streak color differs: Beryl leaves a white streak on unglazed porcelain, Corundum leaves white (colorless). Corundum feels noticeably heavier for its size (specific gravity 3.95–4.10 versus 2.63–2.92 for Beryl).
Which is harder, Beryl or Corundum?
Corundum is harder: Mohs 9 against Mohs 7.5–8 for Beryl.
Which is more valuable, Beryl or Corundum?
Typical specimens of Beryl and Corundum trade in a similar range, around $20.
