Rhondonite, a Mn-bearing silicate mineral, is not to be confused with Rhodochrosite, a Mn-bearing carbonate mineral. Rhondonite is usually a cool, rosy-pink and has a hardness of 5.5-6 which is hard enough to use in a variety of jewelry.
Rhodonite is commonly finely intersperced with black material – a variety of different minerals. It is usually found in metamorphic rocks or igneous rocks that have experienced a lot of hot water percolating through them. Hence, rhodonite is a low-grade ore of Mn and likely to be associated with other Mn-bearing ore minerals.
Colorado, United States
If you go to the website Mindat.org, you will find many localities for Colorado rhodonite – primarily because it is found by mineral collectors in old silver mines scattered throughout the Rockies.