RocksdayAchondrite vs Basalt
To tell Achondrite from Basalt: Earth basalt has no fusion crust and is not a meteorite fall.
A stony meteorite from a melted parent body, so it has no chondrules. The common ones, eucrites, look like a fine basalt and many are thought to come from the asteroid Vesta.
Photo: Claire H., CC BY-SA 2.0
The most common volcanic rock on Earth. Dark, fine-grained lava that forms the ocean floor and vast lava plains.
Photo: James St. John, CC BY 2.0
Key differences
- Earth basalt has no fusion crust and is not a meteorite fall.
Side by side
| Property | Achondrite | Basalt |
|---|---|---|
| Type | Igneous rock | Igneous rock |
| Mohs hardness | 6–7 | 6 |
| Luster | Dull | Dull |
| Streak | White | — |
| Colors | Gray, White, Black | Black, Gray |
| Crystal system / structure | Crystalline stony meteorite | Fine-grained (aphanitic) |
| Specific gravity | 2.8–3.3 | 2.9–3.1 |
| Found in | Millbillillie, Australia; Camel Donga, Australia | Hawaii; Iceland |
Properties that are the same for both are grayed out.
How to identify achondrite
- Fine gray crystalline rock, sometimes with a thin black fusion crust.
- No round chondrules.
- Heavier than a pumice, lighter than an iron. A magnet may tug only weakly, if metal grains are present.
Structure: Crystalline stony meteorite
Full Achondrite guide →How to identify basalt
- Dark gray to black and heavy.
- Grains too small to see.
- Often has gas bubbles (vesicles).
- May show six-sided columns in outcrops.
Structure: Fine-grained (aphanitic)
Full Basalt guide →More comparisons
Frequently asked questions
What is the difference between achondrite and basalt?
Achondrite is an igneous rock with a Mohs hardness of about 6–7 and a dull luster, usually gray, white or black. Basalt is an igneous rock with a Mohs hardness of about 6 and a dull luster, usually black or gray.
How can you tell achondrite from basalt?
Earth basalt has no fusion crust and is not a meteorite fall.
Could you tell them apart from a blurry close-up?
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