corundum

/kɔ'rʌndəm/

Thân thiện

A jeweler examines a piece of corundum under a bright light.

Definition

1. Noun:
   • A very hard mineral: Corundum is a naturally occurring crystalline form of aluminum oxide (Al₂O₃), known for its exceptional hardness, ranking 9 on the Mohs scale of mineral hardness.
   • Used as an abrasive: Due to its hardness, corundum is crushed and used in various abrasive applications, such as in sandpaper, grinding wheels, and polishing compounds.

Examples of Usage

• Noun:
  • The gem-quality varieties of corundum include ruby and sapphire.
  • Industrial-grade corundum is processed to create abrasive powders for machining metals.

Advanced Usage

• "Corundum" in geology and gemology: The term is used specifically to denote the mineral species, with color variations due to trace impurities defining its gem varieties.
  • Geologists identified the deposit as primarily composed of corundum.

Variants and Related Words

• Ruby (n): The red, gem-quality variety of corundum, colored by chromium.
• Sapphire (n): The gem-quality variety of corundum that occurs in all colors except red (which is ruby); most commonly blue, colored by iron and titanium.
• Alumina (n): Another name for aluminum oxide (Al₂O₃), the chemical compound of which corundum is composed.
• Emery (n): A coarse, granular form of corundum mixed with other minerals like magnetite or hematite, used as an abrasive.

Synonyms

• Aluminum oxide: The chemical name for the compound.
• Abrasive mineral: A descriptive term highlighting one of its primary industrial uses.

Related Phrases

• "Corundum grit": Refers to crushed corundum of a specific particle size used for abrasive blasting or grinding.
  • The surface was prepared using corundum grit for better paint adhesion.

Học thuật

Noun

1. very hard mineral used as an abrasive

Từ đồng nghĩa

• corundom