Rhodochrosite
Rhodochrosite is a manganese carbonate, MnCO₃, with the same structure as calcite, in rose-pink to raspberry-red crystals. The name comes from the Greek for 'rose-colored.' It is the national gemstone of Argentina and the state mineral of Colorado.
Rhodochrosite is a manganese carbonate, MnCO₃, with the same structure as calcite, in rose-pink to raspberry-red crystals. The name comes from the Greek for "rose-colored." It is the national gemstone of Argentina and the state mineral of Colorado.
🪨 Geology Guide Specimen: Open Rhodochrosite in the CRV Science Rock & Mineral ID Guide to log the specimen, compare it with the other 8 mineral classes of Dana / Strunz Classes, and test your eye in LithoClade.
Manganese Carbonate: How Is It Like Calcite?
Rhodochrosite has the same trigonal structure as calcite, with manganese in place of calcium, so it shows the same three perfect rhombohedral cleavages. It is slightly harder, at 3.5 to 4, and denser, and it reacts with warm acid.
Occurrence: Where Is It Found?
Rhodochrosite forms in hydrothermal veins of silver, lead and zinc ore, and as sedimentary manganese beds. Superb red crystals come from the Sweet Home Mine in Colorado, while banded pink stalactitic masses from Capillitas in Argentina are called Inca Rose.
Manganese Source: Why Does It Matter?
Rhodochrosite at a Glance
| Property | Value |
|---|---|
| Type / variety | MnCO₃ • Trigonal Manganese Carbonate |
| Composition | MnCO₃ (Isostructural with Calcite) |
| Geology Guide group | Minerals (8 Major Chemical Groups) |
| Mineral Group | Carbonates |
| Mohs hardness | Mohs 3.5–4 |
| Texture / habit | Translucent cherry-red rhombohedra or pink-and-white stalactitic bands |
| Density | 3.50–3.70 g/cm³ |
| Lustre and cleavage | Vitreous raspberry-red to rose-pink with perfect 3-way rhombohedral cleavage |
| Geological setting | Hydrothermal silver-lead-zinc veins (e.g., Sweet Home Mine, Colorado; Capillitas, Argentina) |
| Diagnostic feature (Geology Guide) | Vivid raspberry-red rhombohedral crystals or scalloped rose-pink stalactitic bands (Mohs 3.5–4) exhibiting three perfect rhombohedral cleavage directions and effervescence in warm acid. |
| Formula | MnCO₃ |
| Official status | Colorado state mineral; Argentina national gemstone |