How to identify Fluorite

To correctly identify Fluorite (Fluorite (Calcium Fluoride)), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Extremely variable: purple, blue, green, yellow, colorless, pink, red, brown, black. Often color-zoned.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy).

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically smooth on crystal faces, granular in massive forms.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cubic crystals are most common, often modified by octahedral or dodecahedral faces. Also found as massive, granular, or botryoidal aggregates.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect octahedral cleavage in four directions, producing characteristic triangular or diamond-shaped fragments when broken.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins, pegmatites, carbonatites, sedimentary rocks, and as a gangue mineral in various ore deposits.

Key Facts

Hardness

4 (Mohs scale)

Specific Gravity

3.17-3.18 g/cm

Crystal System

Cubic (isometric)

Color

Extremely variable: purple, blue, green, yellow, colorless, pink, red, brown, black; often color-zoned.

Luster

Vitreous (glassy)

Transparency

Transparent to translucent

Fracture

Subconchoidal to uneven

Cleavage

Perfect octahedral in four directions

Composition

Calcium Fluoride (CaF₂)

Physical characteristics

• Crystal Habit: Cubic, octahedral, dodecahedral crystals; also massive, granular, botryoidal.
• Cleavage Type: Perfect octahedral {111}
• Fracture Type: Subconchoidal to uneven
• Tenacity: Brittle
• Luster Type: Vitreous

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