The Strange Origins of Rhodochrosite

Rhodochrosite forms in cavities of metamorphic rock and is associated with silver. Once known as Rosa del Inca, legends say rhodochrosite was found in abandoned Incan silver mines from the 13th century. Ever since, rhodochrosite has become the national gemstone of Argentina. Hence, this mineral is a byproduct of silver mining. High quality crystals of rhodochrosite were found in the early-1990s at a defunct Colorado silver mine by a team of prospectors, the "Alma King" being the largest known specimen. The rhombohedral crystal measuring-in at 14 cm by 16.5 cm was found at Alma, Colorado at the Sweet Home Mine. Iron, magnesium, and calcium normally discolor the cherry-red crystals found at the mine as naturally occurring inclusions. The pink color of rhodochrosite is due to trace amounts of these inclusions. Miners at Capillitas, Argentina can remove rhodochrosite from a vein and cut slabs of the mineral to be made into cabochons. A typical cabochon is an elongated oval with fleshy pink colored crystals sandwiched between marbled bands of off-white calcite layers. Other cabochons such as those from Japan do not display banding and focus on the rosy red crystals instead. Rhodochrosite appears to the eye like cut & polished agate. Since its a semi-precious gemstone like agate, rhodochrosite increases in value as more expensive gems become more scarce. The softness of this mineral makes it best suited for displays rather than jewelry that would be better suited for agate. When rhodochrosite's found inside a cavity such as those in Argentine, deposits form in layers and form stalactites on the roof or stalagmites on the floor. These specimens are found in Argentina and have a characteristic pink banding. The pink banding of rhodochrosite is characteristic of cutting the stalactite or stalagmite in cross section. First discovered in Sacaramb, Romainia, about the time of 1823 the name was derived from the Greek rhodon meaning "rose red" and chros meaning "color". Rhodochrosite is rarely found in crystalline form, however, crystals were found at the Sweet Home Mine at Alma, Colorado, as mentioned earlier. The Sweet Home Mine was opened as a silver ore mine during the 1870s and remained open until the 1960s. In 1992, the mine reopened to mineral prospectors with considerable success making manganese carbonate the official mineral of Colorado. Some sources say, mineral prospecting at the mine was popular during the late 19th century; however, the mine was in operation at that time. Rhodochrosite is composed of manganese carbonate so it's a source of manganese. Yet, manganese carbonate can interfere with the amalgamation of silver ore. Therefore, the mineral is discarded. Only a handful of places were rhodochrosite has lapidary and mineral usese such as South Africa, Russia, Japan, Gabon, and Mexico. The lapidary use of high quality banded manganese carbonate is for decorative stones. Since rhodochrosite is difficult to cut due to its perfect cleavage, faceted gems of this stone are a rarity.