Rhodochrosite
MnCO₃ · Trigonal · also called inca rose
Rhodochrosite is manganese carbonate and one of the most recognisable pink minerals. Banded stalactitic material from Argentina is widely sold as decorative stone, while transparent red crystals from Colorado are among the most sought-after mineral specimens in the world.
Properties
- Mohs hardness
- 3.5–4
- Streak
- white
- Lustre
- vitreous, pearly
- Colour
- Rose pink to deep raspberry red, very often in concentric pink and white bands.
- Cleavage
- Perfect rhombohedral cleavage, like calcite.
- Fracture
- Conchoidal
- Specific gravity
- 3.4–3.7 (water = 1)
- Magnetism
- Not magnetic
- Acid test
- Fizzes only when powdered
- UV
- Not fluorescent
Tests that confirm rhodochrosite
- Distinctive rose-pink colour with banding in the massive material.
- Effervesces weakly in cold acid, more readily when powdered or warmed.
- Soft: a knife scratches it easily.
What rhodochrosite gets confused with
Each of these is settled by one test. Run that test first.
Rhodonite
Rhodonite is much harder (5.5–6.5), does not fizz, and typically carries black manganese oxide veining.
Calcite fizzes strongly in cold acid; rhodochrosite is more reluctant.
Where it is found
Hydrothermal veins in manganese and silver districts; Argentina, Colorado, Peru, and South Africa.
Is it worth anything?
Banded material is affordable. Gem crystals are seriously expensive.