RocksdayChlorite vs Talc
How to tell them apart
A green, mica-like group of minerals that colors many low-grade metamorphic rocks.
Photo: James St. John, CC BY 2.0
The softest mineral, number 1 on the Mohs scale. It feels soapy or greasy and leaves powder on your fingers.
Photo: Unknown, Public domain
Quick tests
- Streak (rub on unglazed porcelain): Chlorite leaves a pale green streak; Talc leaves white.
Key differences
- Talc is paler and softer.
Side by side
| Property | Chlorite | Talc |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 2–2.5 | 1 |
| Luster | Pearly to dull | Pearly to greasy |
| Streak | Pale green | White |
| Colors | Green | White, Green, Gray |
| Crystal system | Monoclinic | Monoclinic |
| Specific gravity | 2.6–3.3 | 2.7–2.8 |
| Formula | (Mg,Fe)₅Al(Si₃Al)O₁₀(OH)₈ | Mg₃Si₄O₁₀(OH)₂ |
| Found in | Greenschists worldwide; Swiss Alps | Vermont; Montana |
Properties that are the same for both are grayed out.
How to identify chlorite
- Green flaky masses that feel slightly soapy.
- Flakes bend but don't spring back.
- Often inside quartz as green phantoms.
Crystal system: Monoclinic
Full Chlorite guide →How to identify talc
- Easily scratched by a fingernail.
- Slippery, soapy feel.
- Pearly sheen on flaky surfaces.
- Flakes don't spring back when bent.
Crystal system: Monoclinic
Full Talc guide →More comparisons
Could you tell them apart from a blurry close-up?
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