Comparison · Minerals
Andalusite vs Cinnabar
Andalusite and Cinnabar are easy to confuse because both are minerals. Andalusite is harder (Mohs 6.5–7.5) than Cinnabar (Mohs 2–2.5), so Andalusite will scratch Cinnabar and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Andalusite and Cinnabar
- Andalusite is harder (Mohs 6.5–7.5) than Cinnabar (Mohs 2–2.5), so Andalusite will scratch Cinnabar and not the other way round. A fingernail (Mohs 2.5) scratches it easily.
- Streak color differs: Andalusite leaves a white streak on unglazed porcelain, Cinnabar leaves scarlet red.
- Cinnabar feels noticeably heavier for its size (specific gravity 8.0–8.2 versus 3.13–3.21 for Andalusite).
- Hold a thin edge to the light: Andalusite is Transparent to translucent, Cinnabar is Transparent to opaque.
- They overlap in brown, red, and gray, but Andalusite also comes in green and pink.
- Well-formed crystals give it away: Andalusite is Orthorhombic, Cinnabar is Trigonal.
Andalusite vs Cinnabar properties
| Property | Andalusite | Cinnabar |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 6.5–7.5 | 2–2.5 |
| Luster | Vitreous | Adamantine to dull/earthy |
| Streak | White | Scarlet red |
| Transparency | Transparent to translucent | Transparent to opaque |
| Specific gravity | 3.13–3.21 | 8.0–8.2 |
| Crystal system | Orthorhombic | Trigonal |
| Common colors | Reddish brown, Olive green, Gray, Pink | Red, Brownish red, Gray where tarnished |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Andalusite and Cinnabar trade in a similar range, around $20.
About Andalusite
Andalusite is an aluminum silicate, Al2SiO5, and one of three natural polymorphs sharing that exact formula along with kyanite and sillimanite. It crystallizes in the orthorhombic system as stout, nearly square prisms formed under low-pressure, moderate-temperature metamorphism. Its variety chiastolite, which displays a dark cross pattern in cross-section, makes it one of the more recognizable metamorphic minerals to casual collectors.
About Cinnabar
Cinnabar is mercury sulfide, HgS, the principal ore mineral of mercury and one of the most historically significant toxic minerals in human history. It forms a brilliant red to brownish-red mineral typically deposited by low-temperature hydrothermal fluids near volcanic activity and hot springs, often associated with recent or geologically young volcanic terrains. Cinnabar has been mined for millennia both for its metal content and, historically and dangerously, as a pigment source.
Andalusite vs Cinnabar FAQ
Is Andalusite the same as Cinnabar?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Andalusite is harder (Mohs 6.5–7.5) than Cinnabar (Mohs 2–2.5), so Andalusite will scratch Cinnabar and not the other way round. A fingernail (Mohs 2.5) scratches it easily.
How can you tell Andalusite from Cinnabar?
Andalusite is harder (Mohs 6.5–7.5) than Cinnabar (Mohs 2–2.5), so Andalusite will scratch Cinnabar and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Streak color differs: Andalusite leaves a white streak on unglazed porcelain, Cinnabar leaves scarlet red. Cinnabar feels noticeably heavier for its size (specific gravity 8.0–8.2 versus 3.13–3.21 for Andalusite).
Which is harder, Andalusite or Cinnabar?
Andalusite is harder: Mohs 6.5–7.5 against Mohs 2–2.5 for Cinnabar.
Which is more valuable, Andalusite or Cinnabar?
Typical specimens of Andalusite and Cinnabar trade in a similar range, around $20.
