Identification guide · Silicate Minerals
How to Identify Pyrophyllite
Pyrophyllite is usually white, gray, and pale green with a pearly luster and is translucent. It has a Mohs hardness of 1.5. A fingernail (Mohs 2.5) scratches it easily. Its streak is white. It is most often confused with Phlogopite, Serpentine, and Amber; the tests below separate them.
Pyrophyllite identification checklist
| Color | White, Gray, Pale green, Yellow, Brown | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Pearly | Compare a fresh surface with glass and metal; this luster is softer than either. |
| Transparency | Translucent | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 1.5 | A fingernail (Mohs 2.5) scratches it easily. |
| Streak | White | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Perfect basal | |
| Fracture | Uneven | |
| Specific gravity | 2.8 | Ordinary rock-like heft (specific gravity about 2.8), similar to quartz. |
| Crystal system | Monoclinic |
Pyrophyllite look-alikes and how to tell them apart
Phlogopite is harder (Mohs 2.75) than Pyrophyllite (Mohs 1.5), so Phlogopite will scratch Pyrophyllite and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Pyrophyllite vs Phlogopite →
Serpentine is harder (Mohs 3.5) than Pyrophyllite (Mohs 1.5), so Serpentine will scratch Pyrophyllite and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Pyrophyllite vs Serpentine →
Amber is harder (Mohs 2.5) than Pyrophyllite (Mohs 1.5), so Amber will scratch Pyrophyllite and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Pyrophyllite vs Amber →
Andalusite is harder (Mohs 6.5–7.5) than Pyrophyllite (Mohs 1.5), so Andalusite will scratch Pyrophyllite and not the other way round. A fingernail (Mohs 2.5) scratches it easily.
Field tips
- Look for a very soft, pale mineral with a pearly luster and a greasy, slippery feel.
- Pyrophyllite forms foliated and radiating aggregates and can be scratched by a fingernail.
- It is nearly identical to talc, so locality and associated minerals help distinguish the two.
Pyrophyllite identification FAQ
How can you tell if a rock is Pyrophyllite?
Check the color (white, gray, pale green, and yellow), the pearly luster, a Mohs hardness of 1.5 and a white streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Pyrophyllite?
Pyrophyllite has a Mohs hardness of 1.5. A fingernail (Mohs 2.5) scratches it easily.
What is the difference between Pyrophyllite and Phlogopite?
Pyrophyllite (Mohs 1.5, pearly luster) and Phlogopite (Mohs 2.75, pearly luster) look alike, but hardness, streak and heft usually separate them. See the full Pyrophyllite vs Phlogopite comparison for a side-by-side table.
Is Pyrophyllite worth anything?
Entry-level Pyrophyllite specimens sell for around $5, typical collector pieces about $30, and premium examples $150 or more depending on size, quality and locality.
What color is Pyrophyllite?
Pyrophyllite is most often white, gray, pale green, and yellow. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
