Definition

Noun: 1. A type of spinel gemstone: A "spinel ruby" is a specific variety of the mineral spinel that is used as a gemstone. It is characterized by its rich, typically dark red color, which historically led to its confusion with true ruby (corundum).

Usage

• The term "spinel ruby" is used to identify a red gemstone that is mineralogically spinel, not corundum. It specifies both the mineral type (spinel) and its gem-quality appearance (ruby-like).
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Advanced Usage

• The term is primarily used in gemology, jewelry history, and antique descriptions to provide accurate mineralogical identification for stones that may have been historically mislabeled.
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Variants and Related Words

• Spinel (noun): The broader mineral group. A "spinel ruby" is a red gem-quality spinel.
• Ruby (noun): The red gem variety of the mineral corundum. This is a distinct and different mineral from spinel.
• Balas ruby (noun): An archaic synonym for "spinel ruby".

Synonyms

• Red spinel
• Balas ruby (historical term)

Notes on Meaning

• Key Distinction: It is crucial to understand that a "spinel ruby" is not a true ruby. "Ruby" in this compound name refers only to its visual color resemblance, not its mineral composition. True ruby is composed of corundum (aluminum oxide), while spinel ruby is composed of magnesium aluminum oxide.

Noun

1. a spinel used as a gemstone (usually dark red)