What is "ringwoodite"

n. (context mineralogy English) A cubic form of olivine produced under very high pressure, (magnesium, iron²⁺)₂siliconoxygen₄.

Ringwoodite is a high-pressure phase of MgSiO formed at high temperatures and pressures of the Earth's mantle between depth. It is polymorphous with the olivine phase forsterite (a magnesium iron silicate).

Ringwoodite is notable for being able to contain hydroxide ions (oxygen and hydrogen atoms bound together) within its structure.

Combined with evidence of its occurrence deep in the Earth's mantle, this suggests that there is from one to three times the world ocean's equivalent of water in the mantle transition zone from 410 to 660 km deep.

This mineral was first identified in the Tenham meteorite in 1969, and it is inferred to be present in large quantity in the Earth’s mantle.

Ringwoodite was named after the Australian earth scientist Ted Ringwood (1930–1993), who studied polymorphic phase transitions in the common mantle minerals olivine and pyroxene at pressures equivalent to depths as great as about 600 km.

Olivine, wadsleyite, and ringwoodite are polymorphs found in the upper mantle of the earth. At depths greater than about 660 km, other minerals, including some with the perovskite structure, are stable. The properties of these minerals determine many of the properties of the mantle.