Name/Title
Limb CastEntry/Object ID
78.61.104Description
Assemblage Zone: sedimentary
Chemical Composition: Si O2
Crystal System: Hexagonal
Description: Age: Mid-Miocene
Location data: Crooked River, Central Oregon
Description: Greem limbcast variety with polished ends shows blue fortified agate surrounded by green rock and the outer cast is green.
Size: 1 5/8"diameter 2 3/8" length
Type of Fossils Present: Plants
Fracture: conchoidal
Grain Size: Fine
Hardness: 7 Quartz
Lithofacies: Prineville Basalt
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: 1978.61.104Dimensions
Dimension Notes
Dimension taken at widest pointsLocation
Location
Container
CenterDrawer
2nd ShelfShelf
Right, RightWall
SouthBuilding
Mentzer Hall - Petrified Wood RoomCategory
PermanentMoved By
Catherine BoydDate
March 6, 2008Location
Container
CenterDrawer
2nd ShelfShelf
RightCabinet
Case #100Wall
South wallBuilding
Mentzer Hall - Petrified Wood RoomCategory
Permanent
