Bernwoodite

Chemical formula: Ca₅Ti₄+Al₂Si₂O₁₄

An extremely rare silicate of the perovskite supergroup, discovered in river deposits in Brazil, serving as an object of research on the mineralogy of the Earth's mantle.

## Characteristics Bernwoodite is an extremely rare mineral with the chemical formula Ca₅TiAl₂Si₂O₁₄, classified in the perovskite supergroup. Due to its specific formation environment and extreme rarity, it does not form macroscopic crystals, but occurs as microscopic grains. ## Physical properties Due to its occurrence exclusively as microscopic inclusions or individual grains in heavy mineral concentrates, the macroscopic physical properties of bernwoodite are difficult to observe. It crystallizes in the monoclinic system. ## History and name The mineral was identified and described in the 21st century. Its type locality is the river deposits of the Sorriso River (Rio Sorriso placer) in the Juína area, Mato Grosso state, Brazil. ## Uses Bernwoodite has no industrial applications. It is exclusively an object of advanced scientific research, providing information on geochemical processes occurring deep within the Earth.

Properties

Crystal system: Monoclinic

Diagnostic features

## Identification Macroscopic identification of bernwoodite is impossible. Identification requires advanced analytical methods such as X-ray diffraction (XRD) and electron probe microanalysis (EPMA). ## Distinguishing from similar minerals Distinguishing it from other complex silicates and perovskite supergroup minerals relies solely on precise structural studies and determining the exact chemical composition. ## Crystal habits It occurs as microscopic grains. It crystallizes in the monoclinic system, but does not form macroscopically developed crystal forms.

Geological environment

## Origin Bernwoodite is a mineral associated with deep geological processes. The Juína area is famous for the occurrence of diamonds containing inclusions of mantle-derived minerals. This mineral reaches the surface as a result of transport by kimberlitic magmas, and after weathering of the host rocks, it becomes concentrated in river deposits. ## Mineral associations It occurs in heavy mineral concentrates in river deposits, associated with other minerals of mantle origin and weathering-resistant minerals typical of eroded kimberlite pipes. ## Localities The only confirmed occurrence (type locality) is the Sorriso River deposits in the Juína area (Mato Grosso, Brazil).

Rarity

Extremely rare

For collectors

## Quality criteria Bernwoodite does not occur in the form of classic collector specimens. Its value is strictly scientific and systematic. For collectors of rare mineral species, what matters is the mere fact of owning an analytically confirmed fragment of rock or research preparation containing this mineral. ## Popular localities Rio Sorriso in Brazil is the only known source of this mineral, from which the type material originates.

Care and storage

## Cleaning Specimens containing bernwoodite (usually in the form of microscopic grains in matrix rock or special preparations) should be cleaned using distilled water only. Ultrasonic cleaning must be strictly avoided. ## What to avoid Contact with all chemicals, including acids and bases, should be avoided, and specimens should be protected from rapid temperature changes that could cause cracking of the host rock. ## Storage Store in a dry place, preferably in closed micromount boxes, protecting against dust, moisture, and mechanical damage.

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External references

https://www.mindat.org/min-499974.html