Rhodochrosite

Composition
Rhodochrosite generally contains more or less calcium, magnesium, zinc, and iron; hence no sharp distinction can be made between it and the other rhombohedral carbonates. The varieties rich in manganese tend to be of deeper pink color, and the name "manganocalcite" (see calcite) has been used for the manganiferous calcite containing less than 50 percent of manganese carbonate.

**Analyses of rhodochrosite**
1		2
MnO	45.02	MnCO₃	74.99
CaO	11.28	CaCO₃	20.59
ZnO	2.32	ZnCO₃	0.26
MgO	1.76	MgCO₃	3.80
FeO	0.22	FeCO₃	0.36
Fe₂O₃	0.16		100.00
SiO₂	0.32
CO₂	38.92
	100.00

1. Bright-pink material, specific gravity 3.47, Franklin. P. E. Browning (138), analyst.

2. Same with the composition expressed as carbonates, after deducting ferric oxide, willemite equivalent to the silica found, and the excess of zinc oxide, presumably zincite.

Occurrence
At Franklin rhodochrosite was fairly common at the openings on. Mine Hill, chiefly in secondary veins in the ore body. The best crystallized specimens, associated with pyrochroite and radiate fibrous willemite, seem to have come from the Hamburg mine. In the Buckwheat mine rhodochrosite was abundant in veins and granular masses, the matrix of pale-green crystals of willemite. Crystallized druses from the Parker shaft were also seen.

Rhodochrosite was recorded from Sterling Hill by Canfield (136) but was not seen in authentic specimens and must be exceptional.


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	This page created: August 12, 2006 6:49 PM