Yellow Calcite

Physical Properties

Hardness: 3 on Mohs scale; Color: Pale to honey yellow; Luster: Vitreous to waxy; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71

Formation & Geological History

Formed through sedimentary processes, precipitate from calcium-rich groundwater in caves or marine environments, or as a primary mineral in igneous rocks like carbonatite. Geological age varies globally.

Uses & Applications

Used as a decorative gemstone, in carvings, for metaphysical healing collections, and industrially in the production of cement, fertilizer, and as an acid neutralizer.

Geological Facts

Yellow calcite is known for its strong double refraction (birefringence); if you place a clear crystal over a line, it will appear as two separate lines. It is also highly reactive to dilute hydrochloric acid, which will cause it to effervesce (fizz).

Field Identification & Locations

Identify in the field by its rhombohedral cleavage, softness (can be scratched by a copper penny but not a fingernail), and reaction to acid. Often found in limestone quarries or marble deposits.

Identified on: 4/24/2026

Mode: Standard