A member of the Eton public school O.T.C. (Officers Training Corps) practising shouting out orders during a training session, 20th January 1940. (Photo by Hulton Archive/Getty Images)

Two men ride a motorcycle away from a fire in Athens on Friday, July 17, 2015. Greek firefighters battled large brush and forest fires on the outskirts of Athens and in the country's southern Peloponnese region Friday, where flames forced the evacuation of at least three villages and two summer camps. (Photo by Giorgos Bamboukos/InTime News via AP Photo)

Cyril Despres of France tries to get his Peugeot out of the sand as co-pilot David Castera pushes the car during the 10th stage of the Dakar Rally 2016 near Fiambala, Argentina, January 13, 2016. (Photo by Marcos Brindicci/Reuters)

Young U.S. visitors pose for a photograph next to a vintage car in Havana March 16, 2016. (Photo by Ueslei Marcelino/Reuters)

Shokyo Miura, a Buddhist monk and one of the on-site priests, poses for pictures outside Tera Cafe in Tokyo, Japan, April 1, 2016. At first glance, the cafe, which also serves alcohol, looks like any other except for an altar next to the countertop bar with a Buddha statue set against a gold backdrop. The menu confirms this is something different. It lists classes for 1,500 yen ($14) in weaving prayer beads, calligraphy with sutras, or lines of scripture, and consultations with a Buddhist priest. (Photo by Yuya Shino/Reuters)

A young boy scoops water from a hand-dug well in the dry riverbed near Matinyani, in the semi-arid Kitui County in southeastern Kenya, 22 March 2015, the World Water Day. Residents of Kitui County and other arid and semi-arid areas of the country have been hard-hit by extremely poor rainfall this year while the government said in previous month that some 1.6 million people countrywide are facing acute starvation due to the drought and will need relief food over the next six months. Residents of Matinyani say they haven't seen a drop of rain in nearly four months. Thousands of Kenyans in rural areas walk tens of kilometers just to fetch water to drink and to be used in their homes. According to an estimate by UNESCO (United Nations Educational, Scientific and Cultural Organization), 17 million people lack access to safe water in Kenya, where the drought is a perennial problem. (Photo by Dai Kurokawa/EPA)

A couple ride a motorcycle along a street during snow in Altay, Xinjiang Uighur Autonomous Region, China, November 8, 2015. Picture taken November 8, 2015. (Photo by Reuters/Stringer)

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.