Raw amber yellow calcite

Raw Amber (Yellow) Calcite

Educational Overview

Yellow Calcite, often sold as Amber Calcite, is a naturally occurring variety of calcite composed of calcium carbonate (CaCO₃). Its yellow to golden color is typically caused by the presence of iron or other trace mineral inclusions. The material is commonly left in a raw (natural) form, displaying irregular crystal growth, cleavage faces, and natural surface textures.

Calcite crystallizes in the trigonal crystal system and has a Mohs hardness of 3, making it a relatively soft mineral. It is easily scratched and should be handled with care. One of calcite’s defining characteristics is its perfect rhombohedral cleavage, meaning it breaks along smooth, flat planes rather than uneven fractures.

Yellow Calcite forms in sedimentary and hydrothermal environments and is found in many locations worldwide, including Mexico, Brazil, the United States, and Peru. Because calcite is highly reactive to weak acids, it will effervesce (bubble) when exposed to acidic solutions—an important identification feature used in geology.

Other Known Names & Forms of Calcite

Calcite is one of the most widespread minerals on Earth and appears under many names:

Optical & Crystal Varieties

• Iceland Spar

• Optical Calcite

• Clear Calcite

• White Calcite

Color Varieties

• Yellow Calcite / Amber Calcite

• Blue Calcite

• Green Calcite

• Orange Calcite

• Honey Calcite

• Red Calcite

• Mangano Calcite (pink, manganese-rich)

Structural & Geological Forms

• Limestone

• Marble

• Chalk

• Travertine

• Tufa

Trade & Descriptive Names

• Caribbean Calcite (blue calcite with aragonite)

• Onyx Calcite / Mexican Onyx (banded calcite; not true onyx)

• Optical Spar