ARGENTINA'S INCA ROSE

Red roses are a big part of the culture of Argentina. Since European immigrants introduced the flowers in the early 1800s, they have evolved into the beloved, however unofficial, national symbol of love, beauty and strength. The famed rose gardens of Buenos Aires are one of that capitol city's major attractions. Red roses also figure prominently in Argentinian art and festivals; they are even an economic factor as the nation's third largest export.

- STEVE VOYNICK

Another type of "rose" is also ingrained in Argentinian culture-the variety of massive rhodochrosite called "Inca rose." Translucent to opaque and adorned with delicate banding, its colors range from intense rose-red to every shade of pink. Most eye-catching are polished slabs of rare stalactitic Inca rose adorned with their signature patterns of colorful, surreal, concentric rings.

MANGANESE CARBONATE

Rhodochrosite (manganese carbonate, MnCO3) is a member of the calcite group of trigonal carbonates. It has a Mohs hardness of 3.5-4.5, a specific gravity of 3.5-3.6 and, like calcite, perfect, three-directional cleavage. When pure, rhodochrosite is a deep rose-red, a color that calcium and magnesium ions often lighten to pink and zinc ions alter to brownish-yellow.

Although known since antiquity, rhodochrosite was not scientifically described until 1813. Its name stems from the Greek words rhodon, meaning "rose" and chrös, "color."

Rhodochrosite is widely distributed, but uncommon. As a hydrothermal-vein mineral, it occurs primarily as a minor component of multimetal sulfide deposits, with one major exception-Argentina's Capillitas Mining District.

ARGENTINA'S RHODOCHROSITE BONANZA

A remote, 10,000-foot-high mining district in the Andean foothills of northeast Argentina's Catamarca Province, Capillitas is the sole source of Inca rose. This deposit formed seven million years ago when volcanics intruded Paleozoic granite and associated, metal-rich, hydrothermal fluids filled fractures in both the newly emplaced volcanic rock and the surrounding granite.

The Capillitas deposit has 19 known veins, some more than 2,000 feet in length. All consist of rhodochrosite carrying substantial amounts of copper and traces of gold, silver, lead and zinc. The rhodochrosite occurs almost exclusively as banded masses; crystals are rare and less than one-quarter inch in size.