How to identify Apatite

To correctly identify Apatite (Ca5(PO4)3(F,Cl,OH)), 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

   Highly variable; commonly green, blue, yellow, brown, pink, purple, or colorless. Can also be white, gray, or black.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous to sub-resinous.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically crystalline, often forming hexagonal prisms. Can also be massive, granular, or botryoidal.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hexagonal system, typically forming prismatic crystals with pyramidal terminations. Can also be tabular or acicular.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Poor to indistinct on {0001} and {1010}.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Igneous rocks (granites, pegmatites, carbonatites), metamorphic rocks (marbles, gneisses), sedimentary rocks (phosphorites), hydrothermal veins.

Key Facts

Hardness

5 (Mohs scale)

Specific Gravity

3.16 - 3.22

Crystal System

Hexagonal

Color

Highly variable (green, blue, yellow, brown, pink, purple, colorless, etc.)

Luster

Vitreous to sub-resinous

Transparency

Transparent to translucent

Fracture

Conchoidal to uneven

Cleavage

Poor to indistinct on {0001} and {1010}

Composition

Calcium phosphate with fluoride, chloride, or hydroxyl anions

Physical characteristics

• Crystal Habit: Prismatic, tabular, acicular, massive, granular, botryoidal
• Cleavage Type: Poor to indistinct basal and prismatic
• Fracture Type: Conchoidal to uneven
• Tenacity: Brittle
• Luster Type: Vitreous to sub-resinous

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