Rhodochrosite
Last updated: April 2026
Manganese carbonate with intense rose-red to pink color and extreme birefringence. Best known in massive stalactitic form from Argentina ('Inca Rose') with concentric white/pink banding, but transparent faceted crystals also occur.
Rhodochrosite has a specific gravity of 3.50 and a refractive index of 1.600–1.820, with a Mohs hardness of 3.5–4.0. It is uniaxial −.
Physical & Optical Properties
Measured with a polariscope, a refractometer, a hydrostatic balance, a Chelsea filter, a UV torch, a loupe, a darkfield loupe and a spectroscope — step-by-step for each.
Through the refractometer
Drawn from the refractive index above, on a 1.40–1.81 scale. How to take this reading.
Key Differentiators
- Extreme birefringence 0.220 — back facets visibly doubled even to the naked eye
- Very low hardness 3.5–4.0 — easily scratched by a pocket knife
- Concentric banding in massive 'Inca Rose' stalactitic material
- Rose-red to pink color from manganese, no black veins (vs rhodonite)
- SG 3.40–3.70 measurable by hydrostatic weighing
Common Simulants
- Rhodonite: Rhodonite is much harder (5.5–6.5), not scratched by a knife. SG 3.40–3.70 overlaps, and rhodonite's RI (1.716–1.752) sits inside rhodochrosite's broad range — birefringence separates them: 0.014 in rhodonite vs 0.220 in rhodochrosite. Black MnO veins and patches are typical of rhodonite and absent in rhodochrosite.
- Rose Quartz: Rose quartz has RI 1.544–1.553 (much narrower range), hardness 7 (resists knife), SG 2.65 (much lower than rhodochrosite 3.50). No banding. Very low birefringence 0.009. Easy to separate.
- Pink Calcite: Calcite has similar RI range and strong birefringence, but SG only 2.71 versus rhodochrosite 3.50. Much lighter in hand. Hardness also 3.0 vs 3.5–4.0.
- Pink Glass: Glass is singly refractive (no birefringence), RI typically 1.50–1.70, lower SG, no banding. Gas bubbles or swirl marks visible under magnification.
Commonly Confused With
Commonly confused with: Rhodonite, Rose Quartz.
Treatments
- Wax Impregnation
- Dyeing (rare)
Measurement Guides
Identifying a rhodochrosite? Loupewise walks through these tests in order — RI, SG, fluorescence, and more.
Try Loupewise Free →Studying for the GIA, FGA, or FEEG practical? Rhodochrosite is one of the 132 species in Loupewise’s drill and exam pool — practice identifying it from its measured properties under timed exam conditions.
Practice exams →