Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. It streaks white, and its Mohs hardness varies between 3.5 and 4. Its specific gravity is between 3.5 and 3.7. It crystallizes in the trigonal system, and cleaves with rhombohedral carbonate cleavage in three directions.

An Indonesian student protester runs after he caught fire while throwing a molotov cocktail towards police during a protest against the new president's decision to hike fuel prices this week in Makassar, South Sulawesi Province November 19, 2014. (Photo by Yusuf Ahmad/Reuters)

The Waitomo Glowworm Caves attraction is a cave at Waitomo on the North Island of New Zealand, known for its population of glowworms, Arachnocampa luminosa. This species is found exclusively in New Zealand. They are around the size of an average mosquito. This cave is part of the Waitomo Caves system that includes the Ruakuri Cave and the Aranui Cave.

This artist's rendering illustrates the evaporation of HD 189733b's atmosphere in response to a powerful eruption from its host star. NASA's Hubble Space Telescope detected the escaping gases and NASA's Swift satellite caught the stellar flare. (Credit: NASA's Goddard Space Flight Center)

A high temperature alerts were issued as a record-setting summer heat wave continued to bake most parts of south China. (Reuters)

In this photo provided by Skydive Chicago, escape artist Anthony Martin falls while handcuffed and locked inside a box after being dropped from an airplane over Ottawa, Ill., Tuesday, August 6, 2013. (Photo by Joe Silva/AP Photo/Courtesy of Skydive Chicago)

ESA astronaut Tim Peake posted this stunning image on his social media channels, commenting: “Station passed through magnificent aurora Australis last night”. Tim is set to return to Earth on 18 June 2016, bringing his six-month Principia mission to the ISS to an end. During his stay he performed more than 30 scientific experiments for ESA and taking part in numerous others from ESA's international partners. ESA and the UK Space Agency have partnered to develop many exciting educational activities around the Principia mission, aimed at sparking the interest of young children in science and space. (Photo by Tim Peake/ESA/NASA)

Mikhail Vasilenko, a participant from the Siberian town of Nizhny Tagil, works on an ice sculpture called “The Predator”, on the last day of the annual international festival of snow and ice sculptures “The Magical Ice of Siberia”, with the air temperature at about minus 28 degrees Celsius (minus 18.4 degrees Fahrenheit), in Krasnoyarsk, Russia, January 17, 2016. (Photo by Ilya Naymushin/Reuters)