Name/Title
Willow (branch)Entry/Object ID
78.61.32Description
Assemblage Zone: ash flow tuffs
Chemical Composition: Si O2
Crystal System: Hexagonal
Description: Family: Salicaceae
Genus: Salix
Common Name: Willow
Age: Oligocene - Miocene
Location data: John Day Formation, Crook County, Oregon
Description: A limb cast from Prineville, Oregon (central oregon). Only one end is polished on this piece . Colors: dark brown and black wood with two pale cracks. Surrounded by cream at the outer edge also cover entire limb cast
Size: 3.500"x 3.500"x 10.00"
Type of Fossils Present: Plants
Fracture: conchoidal
Grain Size: Fine
Hardness: 7 Quartz
Lithofacies: rhyolitic ash flow
Luster: Glassy
Occurrence: Like petrified wood, limb cast are created in much the same manner. Volcanic ash or silica-rich sediment buries a tree limb, the limb decays, leaving behind an open void. This void works as a mold that fills with amorphous silica that has percolated through the surrounding rock. Once microamorphous silica has filled the mold and the crystallization process to a (quartz)chalcedony or opal is complete, the result is a siliceous rock with the same exterior markings as the original limb.
Pressure: Low-Moderate
Rock Color: Light
Rock Origin: Post-depositional
Rock Type: Sedimentary
Specific Gravity: 2.6
Surface Process: Not apparent
Streak: white
Temperature: Low
Texture: Microcrystalline
Variety: Petrified woods here are hydrous microcrystalline variety of quartz that can be generally termed as chalcedony or opal.Collection
Petrified Wood CollectionAcquisition
Accession
78.61Source or Donor
Delmar Smith Limb Cast CollectionAcquisition Method
DonationOther Names and Numbers
Other Number
Other Number: 1978.61.32Dimensions
Width
3-1/2 inDepth
10 inLength
3-1/2 inDimension Notes
Dimension taken at widest pointsLocation
Location
Display Case
PW-8Room
Petrified Wood RoomBuilding
Crater Rock MuseumCategory
ExhibitMoved By
Jillian Mather KettleyDate
May 28, 2025Notes
Location update
