Comparison · Silicate Minerals
Phlogopite vs Serpentine
Phlogopite and Serpentine are easy to confuse because both are silicate minerals. Both sit near Mohs 2.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Phlogopite and Serpentine
- Both sit near Mohs 2.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- They overlap in yellow and green, but Phlogopite also comes in brown and red and Serpentine also comes in black and white.
Phlogopite vs Serpentine properties
| Property | Phlogopite | Serpentine |
|---|---|---|
| Type | Silicate Minerals | Silicate Minerals |
| Mohs hardness | 2.75 | 3.5 |
| Luster | pearly | greasy |
| Streak | White | White |
| Transparency | translucent | translucent |
| Specific gravity | 2.8 | 2.6 |
| Crystal system | monoclinic | monoclinic |
| Common colors | Brown, Yellow, Tan, Reddish brown, Green | Green, Yellowish green, Olive, Black, White |
| Rarity | common | common |
| Typical specimen value | $5–$250+ | $5–$250+ |
Which is more valuable?
Typical specimens of Phlogopite and Serpentine trade in a similar range, around $40.
About Phlogopite
Phlogopite is a magnesium-rich member of the mica group, recognized by its brown to tan color and perfect basal cleavage that splits into thin, flexible, elastic sheets. It typically forms tabular or pseudohexagonal crystals in marbles and magnesium-rich rocks.
About Serpentine
Serpentine is a group of green, magnesium-rich silicate minerals that includes antigorite, lizardite, and chrysotile. It commonly occurs as massive, greasy-feeling rock in mottled green tones and is the main component of the rock serpentinite.
Phlogopite vs Serpentine FAQ
Is Phlogopite the same as Serpentine?
No. Both are silicate minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 2.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Phlogopite from Serpentine?
Both sit near Mohs 2.75, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. They overlap in yellow and green, but Phlogopite also comes in brown and red and Serpentine also comes in black and white.
Which is harder, Phlogopite or Serpentine?
Serpentine is harder: Mohs 3.5 against Mohs 2.75 for Phlogopite.
Which is more valuable, Phlogopite or Serpentine?
Typical specimens of Phlogopite and Serpentine trade in a similar range, around $40.
