Name/Title
Prehnite w/ Garnet & EpidoteEntry/Object ID
2023.7.45Description
About Prehnite
Formula: Ca2Al2Si3O10(OH)2
Colour: Colourless to gray to yellow, yellow-green or white
Lustre: Vitreous, Pearly
Hardness: 6 - 6½
Specific Gravity: 2.8 - 2.95
Crystal System: Orthorhombic
Name: Named in 1788 by Abraham Gottlieb Werner in honor of the Dutch Colonel, Hendrik von/van Prehn [July 31/August 2, 1733 Cape of Good Hope Colony - August 1785 Heilbronn, Wurttemberg {Germany}], who is credited with discovering the mineral in 1774 at the Cape of Good Hope in South Africa. Von Prehn was a governor of Cape of Good Hope (1779-1780) until he was dismissed. He was a naturalist and mineral collector who brought the first specimens of his namesake mineral to Europe. It is unknown how the mineral came to the attention of Werner. A considerable mystique and folklore have surrounded Prehn and prehnite. The appellation "von" was supposedly bestowed on Prehn for his military service during the Seven Year's War, but there are no printed records available to substantiate the claim. It has been claimed that prehnite was the first mineral named for a person. In 1813, Richard Chenevix wrote a lengthy article (100+ pages) decrying the naming of minerals for people.)
Type Locality: Karoo dolerites, Cradock, Inxuba Yethemba Local Municipality, Chris Hani District Municipality, Eastern Cape, South Africa
The Al analogue of ferriprehnite. Both seem to belong to the prehnite group that also likely contains amstallite.
A relatively common calcium alumosilicate occurring in low-temperature hydrothermal environments.
Colourless brick-shaped crystals may be confused with stellerite.Collection
John Morrow CollectionLocation
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
December 27, 2023