Type Locality
Formula: CuI
Occurrence: Very Rare
Named after Australian C.W. Marsh who first described the mineral.
| Colour | Colourless or pale yellowish when fresh. Darkens to salmon-pink to brownish-red on exposure. |
| Lustre | Sub-Adamantine, Greasy |
| Hardness | 2.5 |
| SG | 5.68 |
| Crystal System | Cubic |
| Fluorescence | Bright red under longwave UV |
Usually occurs as tetrahedral crystals that can alter colour upon prolonged exposure. Highly fluorescent. Many previously unknown marshite specimens have been “discovered” since the arrival of the Convoy-type UV torches.
Cuprite is the most common associate.