How to identify Fluorite

To correctly identify Fluorite (Fluorite), 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 or banded.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy).

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth to slightly rough on crystal faces; conchoidal fracture surfaces are smooth.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Typically cubic, octahedral, or dodecahedral crystals. Also massive, granular, or botryoidal habits.

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.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins, often associated with metallic ore deposits (e.g., lead, zinc, silver). Also found in pegmatites, carbonatites, and as an accessory mineral in some igneous and metamorphic rocks. Can occur in sedimentary rocks as a diagenetic or evaporite mineral.

Key Facts

Hardness

4 (Mohs scale)

Specific Gravity

3.17-3.18 g/cm

Crystal System

Isometric (Cubic)

Color

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

Luster

Vitreous

Transparency

Transparent to translucent

Fracture

Conchoidal to uneven

Cleavage

Perfect octahedral in four directions {111}

Composition

Calcium Fluoride (CaF₂)

Physical characteristics

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

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