| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | aluminium oxide | gemstone industry | Aluminium oxide is known as corundum and is highly valued as a gemstone, particularly in the forms of sapphires and rubies. | 1 |
| 2 | aluminum oxide | gemstone industry | Aluminum oxide, in the form of synthetic sapphires and rubies, is highly valued as a material for creating jewelry and luxury items. | 1 |