Name/Title
LaumontiteEntry/Object ID
2009.62.17Description
Chemical Composition: CaAl2Si4O12-4H2O
Crystal System: Monoclinic System
Description: Common Name: Laumontite
Chemistry: CaAl2Si4O12-4H2O
Group: Zeolite
Location: Wipple Quarry, Drain, Oregon USA
Description: Very brittle, not metalic, spine like crystals.
PHYSICAL CHARACTERISTICS:
Color is colorless or white and tinted pink, gray, almond yellow or brown.
Luster is vitreous to dull on exposure to light.
Transparency: crystals are transparent to translucent and opaque with exposure to light.
Crystal System is monoclinic; 2 or m
Crystal Habits include nearly square prisms terminated by the flat, slanted face of a pinacoid. also massive, fibrous and radiating. Some good penetration twins are found.
Cleavage is perfect in two directions, forming splinters.
Fracture is uneven.
Hardness is less than 4
Specific Gravity is approximately 2.2+ (very light)
Streak is white.
Other Characteristics: crystals are commonly grooved or striated, and cleavage surfaces have a pearly luster.
Associated Minerals are quartz, calcite, apophyllite, babingtonite, heulandite, natrolite and other zeolites.
Best Field Indicators are crystal habit, luster, density, alteration, and associations.
Fracture: uneven
Hardness: 3 Calcite
Luster: Vitreous
Occurrence: It is found in hydrothermal deposits left in calcareous rocks, often formed as a result of secondary mineralization. Host rock types include basalt, andesite, metamorphic rocks and granites.
Rock Type: Sedimentary
Specific Gravity: 2.2
Streak: White
Texture: crystaline
Variety: Laumontite is a mineral, one of the zeolite groupa hydrated calcium-aluminium silicate. Potassium or sodium may substitute for the calcium but only in very small amounts.
It is monoclinic, space group C2/m. It forms prismatic crystals with a diamond-shaped cross-section and an angled termination. When pure, the color is colorless or white. Impurities may color it orange, brownish, gray, yellowish, pink, or reddish. It has perfect cleavage on [010] and [110] and its fracture is conchoidal. It is very brittle. The Mohs scale hardness is 3.5-4. It has a vitreous luster and a white streak
Laumontite easily dehydrates when stored in a low humidity environment. When freshly collected, if it has not already been exposed to the environment, it can be translucent or transparent. Over a period of hours to days the loss of water turns it opaque white. In the past, this variety has been called leonhardite, though this is not a valid mineral species. The dehydrated laumontite is very friable, often falling into a powder at the slightest touch.Collection
RAGM Mineral CollectionAcquisition
Accession
2009.62Source or Donor
Museum Collection of MineralsAcquisition Method
DonationDimensions
Width
4 inDepth
2-1/2 inLength
4 inWeight
1.08 ozDimension Notes
Dimension taken at widest pointsLocation
Location
Shelf
CS-D-2Room
Curation StorageBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
May 24, 2023Notes
Added current locationLocation
Drawer
2nd from RightShelf
Left 3rd Shelf, Left 3rd ShelfWall
SouthRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Scott LonganDate
August 5, 2009Location
Container
RightDrawer
3rd shelfShelf
Left side, Left sideWall
South wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Scott LonganDate
August 5, 2009Location
Container
LeftDrawer
2nd ShelfShelf
CenterCabinet
Case #41Wall
South wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
Permanent