Lepidolite

KLi2AlSi4O10F2

Lepidolite is a silicate mineral prized by collectors for its exceptional color range.

Crystal Structure
Li-mica.
Elemental Composition (by mass)
ElementMass %Visual
O Oxygen40.99%
Si Silicon28.78%
K Potassium10.02%
F Fluorine9.74%
Al Aluminum6.91%
Li Lithium3.56%
Computed from simplified end-member formula. Solid-solution series, water content, and trace substitutions cause real-world variation.
IMA Abbreviation (Whitney-Evans 2010)
Lpd
→ Lepidolite
Li-mica
Standard symbol from American Mineralogist (Whitney & Evans, 2010). Used in thin-section labeling, phase diagrams, and IMA-style species records.
Pronunciation
/lɪˈpɪdəlaɪt/
lih-PID-uh-lite
Greek lepis (scale)
Tenacity
Behavior:
elastic
Under stress:
Springs back
Same.
Luster
pearly
Lavender-pink sheets.
Diaphaneity (Transparency)
translucent
Pinkish-violet lithium mica.
Type Locality
Rožná — Czech Republic
Described 1792 by Klaproth
› Browse all type localities
Magnetism
Category:
diamagnetic
Test result:
Slight repulsion possible
Li-rich mica — diamagnetic baseline.
Test with rare-earth magnet (N42 or N52 neodymium). Suspend specimen on thread for sensitive paramagnetic detection. Diamagnetic minerals are weakly repelled (visible only with strong magnets like bismuth).
Specific Gravity
2.80–2.90
g/cm³
light
Li-rich mica.
For comparison: water = 1.00, glass ≈ 2.5, quartz = 2.65, corundum ≈ 4.00, galena ≈ 7.50, gold ≈ 19.3.
Geological Setting
Environment:
pegmatite
Host rock:
lithium-rich pegmatite
Companions:
Tourmaline · Spodumene · Feldspar · Beryl
Diagnostic mineral of lithium-rich pegmatite environments.
Cleavage & Fracture
Cleavage:
perfect 1 direction {001} — basal
Fracture:
uneven
Pinkish-lavender sheets.
Collector tier: Solid Display
Reliable mid-tier display species. Easy to find in well-formed examples; broad locality diversity.
Often found withTourmaline · Spodumene · Quartz · Cleavelandite
Mohs 2.5–4
Vickers (~) 170 HV
Knoop (~) 185 HK
Geological setting
Pegmatite
Element composition by mass

Formula: K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂ · molar mass: 396.11 g/mol

O 44.43%
Al 23.84%
Si 14.18%
K 9.87%
F 4.8%
Li 2.63%
H 0.25%

Computed from atomic weights (IUPAC 2021). Site-occupancy groups (Fe,Mn) split equally.

GroupMica Group
Related members: Muscovite · Biotite · Phlogopite
Mohs Hardness 2.5–4

Lepidolite sits at 2.5–4 on the Mohs scale — can be scratched by a steel knife.

Colors:
Streak
White
Crystal system
Monoclinic
SilicatesSilicates (Phyllosilicates — Micas)
TL;DR · 1 min read
Lepidolite (K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂) is the lithium-bearing mica, distinctive for its lavender to pink color and book-like aggregates of glittering scales. It is a major lithium ore mineral and the most-collected lithium mica.

Lepidolite (K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂) is the lithium-bearing mica, distinctive for its lavender to pink color and book-like aggregates of glittering scales. It is a major lithium ore mineral and the most-collected lithium mica. Pegmatites at Coronel Murta (Brazil), Pala (California), and Madagascar produce iconic specimens, often paired with rubellite tourmaline.

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Other Members of the Mica Group

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