You’ve known how to name 3D shapes since elementary school. They’re easy: cube. Cylinder. Pentagonal dodecahedron?
Among our many Exhibits in the Rice Northwest Rock and Mineral Museum is our popular Rhodochrosite specimens. Rhodochrosite is also known as Inca Rose Stone, Raspberry Spar, and Manganese Spar.
Rhodochrosite is a manganese carbonate (MnCO3). The carbonates are a group of minerals that contain the anion group CO32-, and are subdivided into the calcite, aragonite, dolomite or hydrated carbonate subgroups. Rhodochrosite belongs to the calcite subgroup. These carbonates are known for having rhombohedral symmetry, which results in the formation of rare rhombohedron shaped crystals.
The name rhodochrosite is derived from the Greek for rose-colored. Rhodochrosite is most commonly pink or red, but may sometimes occur as yellow, grey or brown crystals. Pink and red colors occur when the rhodochrosite has a high manganese content, but some substitution of iron in place of manganese causes other colors. Its density also depends on the amount of manganese present, with a lower density associated with low iron content. Continue reading
We are excited to feature some malachite lapidary work from the Democratic Republic of Congo (formerly Zaire) in our Lapidary Arts Room for only the month of March 2012. Make time to visit this rare and special collection at the Rice Northwest Rock and Mineral Museum.
Carbonates are a group of minerals that contain the anion group CO32. They can be subdivided into the calcite, aragonite, dolomite or hydrated carbonate groups. The mineral malachite belongs in the hydrated (OH-bearing) carbonate group. It is a copper (Cu) bearing mineral and has the chemical formula Cu2CO3(OH)2. Continue reading