How to identify Lepidolite

To correctly identify Lepidolite (K(Li,Al)3(Al,Si)4O10(F,OH)2), 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

   Typically lilac, pink, or purple; less commonly gray, white, or yellowish.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous to pearly on cleavage surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Scaly, platy, or granular aggregates; individual crystals are tabular.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Pseudohexagonal tabular crystals, often forming aggregates of small scales, rosettes, or massive forms.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect basal cleavage (001), allowing it to be split into thin, flexible sheets.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Exclusively found in lithium-rich granitic pegmatites, often associated with quartz, feldspar, spodumene, tourmaline, and beryl.

Key Facts

Hardness

2.5-3.5 on the Mohs scale

Specific Gravity

2.8-2.9

Crystal System

Monoclinic

Color

Lilac, pink, purple, gray, white, yellowish

Luster

Vitreous to pearly

Transparency

Transparent to translucent

Fracture

Uneven to splintery

Cleavage

Perfect basal cleavage (001)

Composition

Potassium lithium aluminum silicate hydroxide fluoride

Physical characteristics

• Crystal Habit: Tabular, platy, scaly aggregates, massive, radiating rosettes
• Cleavage Type: Perfect basal cleavage on {001}
• Fracture Type: Uneven to splintery
• Tenacity: Flexible and elastic in thin sheets
• Luster Type: Vitreous to pearly

Explore Lepidolite