Davemaoite

Chemical formula: CaSiO₃

Davemaoite is a high-pressure calcium silicate with a perovskite structure, occurring naturally as microscopic inclusions in diamonds.

## Characteristics Davemaoite is a mineral with a perovskite structure, representing a high-pressure form of calcium silicate (CaSiO₃). Under Earth's surface conditions, it is unstable and transforms into other minerals. It occurs exclusively as microscopic, submicron inclusions trapped in diamonds originating from the Earth's lower mantle. For this reason, it is not possible to observe it in the form of macroscopic crystals. Its existence was theoretically predicted and confirmed under laboratory conditions long before its discovery in nature. ## Physical Properties As a mineral observed only on a micro-scale, most of its physical properties are extrapolated from laboratory and theoretical data. The calculated density is approximately 4.27 g/cm³. Hardness and other mechanical characteristics have not been measured on natural material. ## Colors and Varieties Natural davemaoite inclusions are too small to determine their color with the naked eye. Microscopic observations indicate that it is transparent and colorless. It has no varieties. ## History and Name The mineral is named in honor of Ho-kwang "Dave" Mao (born 1941), a distinguished geophysicist and pioneer of high-pressure research at the Carnegie Institution for Science in Washington. The mineral was officially approved by the International Mineralogical Association (IMA) in 2021. Its discovery in nature, made by a team led by Oliver Tschauner, represented a breakthrough, confirming the presence of this important mineral phase in the Earth's lower mantle. ## Uses Davemaoite has no commercial or industrial applications. Its significance is purely scientific, as a key mineral forming the Earth's lower mantle and an indicator of geochemical processes occurring at extreme depths.

Properties

Density: 4.27
Cleavage: None
Transparency: Transparent
Crystal system: Isometric

Diagnostic features

## Identification Identification of davemaoite is impossible without advanced laboratory techniques. It requires the use of synchrotron X-ray diffraction on a microscopic inclusion within a diamond. This is the only method that allows confirmation of its unique, isometric crystal structure. ## Distinguishing from Similar Minerals Davemaoite is a high-pressure polymorph of wollastonite and breyite. Under surface conditions, wollastonite (crystallizing in the triclinic system) is the stable form of CaSiO₃. Davemaoite differs from them in its crystal structure (isometric perovskite), which can only be identified by diffraction methods. ## Crystal Forms Observed natural inclusions are in the form of submicron, cubic or near-cubic crystals, which is consistent with its isometric crystallographic system.

Geological environment

## Genesis Davemaoite crystallizes under conditions of extremely high pressure (above 20 GPa) and temperature, prevalent in the Earth's lower mantle, at depths of approximately 660 to 2700 km. It forms as a result of the phase transformation of other calcium silicates. The only known natural samples were brought to the surface as inclusions in superdeep diamonds, which acted as a pressure capsule, protecting the mineral from decomposition during rapid transport to the surface in kimberlites. ## Mineral Associations This mineral co-occurs with diamond (as an inclusion within it). In the same diamond where it was discovered, the presence of other high-pressure minerals, such as ferropericlase and other yet unidentified phases, was also confirmed. ## Localities The only confirmed natural locality for davemaoite is the Orapa diamond mine in Botswana. This is where the diamond in which this mineral was identified originated.

Rarity

Extremely rare

For collectors

## Quality Criteria Davemaoite is not a collector's mineral in the traditional sense. It does not form specimens that can be collected and evaluated for aesthetic appeal. Its value is purely scientific. Theoretically, a diamond containing a confirmed davemaoite inclusion would be an object of immense scientific and potentially material value for research institutions, but not for a typical mineral collector. ## Market Prices Not applicable. Davemaoite is not traded on the collector's market. ## Popular Localities The only known and confirmed locality is the Orapa mine in Botswana.

Care and storage

## Cleaning Not applicable. This mineral occurs exclusively as microscopic inclusions in diamonds and is not available as a separate specimen for cleaning. ## What to Avoid Not applicable. Davemaoite is unstable under Earth's surface conditions. Any specimen released from the diamond in which it is trapped would immediately undergo a phase transformation. ## Storage The only form of "storing" davemaoite is to preserve the parent diamond intact. The diamond acts as a natural, high-pressure container that protects the inclusion from decompression and transformation.