Agate vs Jasper
Agate and Jasper are commonly confused, and 1 measured property separates them — density most clearly.
Agate vs Jasper
Agate
Banded chalcedony — quartz in crystals too small to see, deposited in rhythm inside a cavity.
Jasper
Opaque chalcedony full of other minerals — and it is the impurities that make it worth looking at.
| Property | Agate | Jasper |
|---|---|---|
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | trigonal | trigonal |
| Density | 2.58–2.64 g/cm³ | 2.5–2.9 g/cm³ higher |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 6.5–7 | 6.5–7 |
Why these get confused
translucent against opaque, and a single specimen is often both — the boundary is a judgement rather than a composition
The confusion is a real and documented one, not a resemblance we have invented.