Gem-name guide / Gem variety

Pleonaste

MgAl₂O₄

Pleonaste is indexed as a gem variety in this gem-name directory. The CIBJO nomenclature table associates this name with Spinel. Gem names may describe appearance or a material family; a name alone does not identify treatments, origin or quality.

Material or mineral family: Spinel
Name classification: Gem variety
Related names / synonyms: Black Spinel

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Names describe materials, not the authenticity, treatment, provenance or quality of a particular specimen. Physical properties vary for mixed materials; values absent from this guide have not been estimated.

Reference snapshot: September 2026. Source dates and uncertainties are retained in the record.