Beautiful rose red to pink rhodochrosite crystals are popular with mineral collectors. Although very soft, opaque stones have been fashioned into beads, cabochons, and carvings, while very rare translucent to transparent material has been cut into faceted gems.
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Rhodochrosite belongs to two solid solution series. It’s the manganese (Mn) analogue in a series with iron (Fe)-dominant siderite. It holds the Mn-end of a series with calcium (Ca)-dominant calcite, too.
Does Rhodochrosite Make a Good Jewelry Stone?
With perfect cleavage, low hardness, and heat sensitivity, rhodochrosites make challenging stones to cut and wear. Nevertheless, in protective settings, these gems can serve as beautiful stones for a variety of jewelry uses.
Massive material from Argentina occurs in large pieces. Gem cutters have cabbed and carved this material into decorative as well as useful objects, such as boxes. Aggregate rhodochrosites can show white or grey jagged bands. Facetable, translucent pink material cuts stones up to about 20 carats.
“Raspberry Swirl,” rhodochrosite and garnet necklace with sterling silver accents. Jewelry and photo by Lee. Licensed under CC By-ND 2.0.
The Capillitas mine in Argentina’s Catamarca Province has also produced very rare trapiche-like rhodochrosites. Some sections of stalactitic rhodochrosites have revealed stunning, star-like “floral” patterns.
South African rhodochrosites have a rich, rose red color but rarely occur in facetable crystals. The largest cut gems are in the 60-carat range.
Colorado produces pink gems, perhaps the loveliest of all. Faceters have cut flawless gems up to about 15 carats. However, most stones range under five carats in size.
Calcium in rhodochrosite’s formula reduces its refractive index (RI) and specific gravity. Iron and zinc, in contrast, increase them. This also affects its birefringence. High birefringence causes a pronounced doubling effect in rhodochrosites.
Single crystals may be zoned, causing the RI to vary up to 0.01 within a space of one inch in some material.
Rhodochrosites will effervesce in warm acids. Please keep in mind that acid testing is a destructive test that can endanger both the gem and the tester. Never conduct this test on a finished gem. Use this procedure as a last resort for gem identification only.
Rhodonites and rhodochrosites may be misidentified due to their color and appearance. Furthermore, both are popular materials for decorative and practical carvings. Opaque rose-red rhodonites can also show banding, though it appears darker and dendritic. Like rhodochrosites, rare transparent rhodonites may also be faceted. However, rhodonites have greater hardness and different optical properties.
Are There Synthetic Rhodochrosites?
Since rhodochrosite serves as an important manganese ore, scientists have synthesized this material for research purposes. Synthetic material has also appeared in jewelry, particularly as beads and cabs.
Opaque rhodochrosites may receive wax or plastic impregnation to improve durability and color, and hot point testing may reveal this. However, hot point testing is also a destructive test.
Where are Rhodochrosites Found?
The American state of Colorado produces spectacular crystals, pink to deep red, up to three inches on an edge. The world’s finest facetable rhodochrosite comes from Alma, Colorado. Other Colorado localities also produce pink faceting rough.
San Luis, Catamarca Province, Argentina produces massive and banded material, including stalactites up to four feet long! These have concentric structures that display interesting “bull’s eyes” when cross-sectioned. Some Argentinian material is also translucent and facetable.
Other notable sources include the following:
Butte, Montana: crystal groups (non-gem).
Magdalena, Mexico: sometimes in cuttable pieces.
Peru: facetable, pink crystals.
Hotazel, South Africa: facetable, deep reddish crystals.
Smithsonian Institution (Washington, DC): 20.8, 15.2, and 9.5 carats (South Africa).
Devonian Group (Calgary, Alberta, Canada): 5.95 (red, South Africa).
National Museums of Canada (Ottawa, Ontario): 18.05 (red oval, South Africa).
Private Collection: 59.65 (red oval, South Africa).
Avoid cleaning any rhodochrosites with mechanical systems and any cleaning solutions with acids. Instead, use a soft brush, mild detergent, and warm water only.
Be aware that the temperatures a jeweler’s torch reaches can damage plastic or wax-impregnated gems. Therefore, if you don’t know if your loose rhodochrosites are treated, have them tested by a gemological lab before setting.
Store your rhodochrosites separately from other stones to avoid contact scratches.