AllMineralsRock
Corundum
Corundum is a very popular mineral composed of aluminum oxide. [1]
Corundum: Quick Facts and Characteristics
Some quick facts for Corundum:- Transparency: Corundum can be opaque, translucent or transparent.
- Crystallography: In terms of crystallography, corundum can be hexagonal or trigonal.
- Luster: In terms of luster, corundum can be adamantine or vitreous (glassy).
- Streak: Corundum streaks white.
- Hardness: Corundum's hardness is 9 on the Moh's scale.
- Specific Gravity: Corundum's specific gravity ranges from 3.99 to 4.
Corundum: Background and Summary
Corundum is a mineral that is commonly found in metamorphic and igneous rocks. It is composed of aluminum oxide and can be identified by its hardness and crystal structure. Corundum has a hardness of 9 on the Mohs scale, making it one of the hardest minerals known to man. Its crystal structure is hexagonal, with six-sided prisms and pyramids that form a beautiful and distinctive crystal habit.Corundum is widely used in industry due to its hardness and resistance to wear and tear. It is commonly used as an abrasive in sandpaper, grinding wheels, and polishing compounds. It is also used in the production of refractory materials, such as furnace linings and crucibles, due to its high melting point and resistance to heat. Additionally, corundum is used in the production of advanced ceramics, such as cutting tools, ball bearings, and electronic components.
In addition to its industrial uses, corundum is also used in jewelry. The most well-known variety of corundum is the gemstone ruby, which is a red variety of corundum. Another popular variety of corundum is sapphire, which can be found in a range of colors, including blue, yellow, green, and pink. Corundum is also sometimes used as a substitute for diamonds in engagement rings and other jewelry.
Corundum: Table of Properties
| Attribute | Corundum (src) |
|---|---|
| Transparency | transparent, translucent, opaque |
| Chemical Formula | Al2O3 |
| Chemical Composition | aluminum oxide |
| Specific Gravity | 3.99, 4, 4.1 |
| Hardness | 9 |
| Streak | white |
| Crystallography | hexagonal, trigonal |
| Refractive Index | 1.757, 1.779 |
| Hydrous | No |
| Colors | common: green, red, blue, pink, brown sometimes: amber, yellow, colorless less common: gray, black, white, orange, purple, violet, striped, gold, multicolor |
| Solubility | Insoluble |
| Fracture | 1: 1 |
Corundum: FAQ
Q: Is corundum rare?A: Corundum is not considered a rare mineral, but high-quality gemstone specimens can be quite valuable.
Q: Can corundum be found in the United States?
A: Yes, corundum can be found in several locations in the United States, including North Carolina, Montana, and Wyoming.
Q: Is corundum toxic?
A: No, corundum is not toxic and is safe for handling.
Q: Can corundum be synthesized?
A: Yes, corundum can be synthesized in a laboratory setting using a process known as the Verneuil process.
Sources
- "Corundum." Mindat.org. https://www.mindat.org/min-1148.html- "Corundum." Geology.com. https://geology.com/minerals/corundum.shtml
- "What is Corundum and What are its Basic Qualities?" GIA. https://www.gia.edu/corundum-description
- Corundum: https://en.wikipedia.org/wiki/Corundum
Previous Mineral: acanthite Next Mineral: sanidine