Name/Title
Limb CastEntry/Object ID
07.58.108Description
Chemical Composition: Si O2
Crystal System: Hexagonal
Description: Age: Probably Miocene
Location data: Upper-east Evans Creek, Jackson Co, Oregon USA
Description: Bob found this on the upper east end of Evans Creek in Jackson County. Butt cut limb cast, polished face brown, tan and reddish-brown with white agate veins and crystal-quartz material, outer mostly covered with reddish brown woody appearance.
Size: Diameter: 6" Length: 3"
Type of Fossils Present: Plants
Fracture: conchoidal
Grain Size: Fine
Hardness: 7 Quartz
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: Medium
Rock Origin: Post-depositional
Rock Type: Sedimentary
Specific Gravity: 2.6
Surface Process: Not apparent
Temperature: Low
Texture: Microcrystalline
Variety: Petrified woods ar hydrous microcrystalline varieties of quartz that can be generally termed as chalcedony or opalized .Collection
Petrified Wood CollectionAcquisition
Accession
07.58Source or Donor
Petrified Wood CollectionAcquisition Method
DonationOther Names and Numbers
Other Number
Other Number: 2007.58.108Dimensions
Length
3 inDiameter
6 inDimension Notes
Dimension taken at widest pointsLocation
Location
Shelf
2nd shelf on right, 2nd shelf on rightWall
right - southRoom
Wood roomBuilding
Mentzer Hall - Petrified Wood RoomCategory
PermanentMoved By
Catherine BoydDate
March 6, 2008Location
Container
LeftDrawer
Bottom / Back RowShelf
Right, RightWall
SouthBuilding
Mentzer Hall - Petrified Wood RoomCategory
PermanentMoved By
Catherine BoydDate
March 6, 2008Location
Container
LeftDrawer
Bottom / Back RowShelf
RightCabinet
Case #100Wall
South wallBuilding
Mentzer Hall - Petrified Wood RoomCategory
Permanent
