marcasite

A jeweler examines a marcasite brooch under a bright lamp.

Definition

Noun:
- A mineral: "marcasite" is a mineral composed of iron sulfide (FeS₂), chemically identical to pyrite but with a different crystal structure. It is typically pale bronze-yellow in color and often forms in a radiating, fibrous, or stalactitic habit.
- A gemstone imitation: In jewelry, "marcasite" commonly refers to small, faceted pieces of pyrite (not true marcasite) used as a decorative inlay, typically in silver settings, to create a sparkling, metallic effect.

Usage Examples

Mineral context:
- The geologist identified the specimen as marcasite due to its distinctive radiating crystal structure. (A mineral with a specific crystal form.)
Jewelry context:
- She wore a vintage silver brooch set with marcasite stones. (Decorative, faceted pyrite pieces used in jewelry.)

Advanced Usage

"marcasite jewelry": a style of jewelry that uses small, shiny pyrite pieces (often misnamed marcasite) set in silver or other metals.
- Marcasite jewelry was especially popular in the Victorian era. (A vintage jewelry style featuring pyrite accents.)

Variants and Related Words

Marcasitic (adj): relating to or resembling marcasite.
- The mineral sample had a marcasitic luster. (Having the appearance or properties of marcasite.)

Synonyms

White iron pyrite: an older, less common term for marcasite due to its paler color compared to pyrite.
Spear pyrite: a descriptive name for marcasite's typical crystal shape (resembling a spearhead).

Related Idioms