Limb Cast

Object/Artifact

-

Crater Rock Museum

Name/Title

Limb Cast

Entry/Object ID

07.58.75

Description

Chemical Composition: Si O2 Crystal System: Hexagonal Description: Age: Tertiary Location data: Texas Springs, Elko Co., NV. USA Lower Miocene Humboldt Fm. Description: Size: Length 6.75 - face 2.5 x 1.5 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: Light 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 Collection

Acquisition

Accession

07.58

Source or Donor

Petrified Wood Collection

Acquisition Method

Donation

Other Names and Numbers

Other Number

Old Number: F870; Other Number: 2007.58.75

Dimensions

Width

2-1/2 in

Depth

1-1/2 in

Length

6-3/4 in

Dimension Notes

Dimension taken at widest points

Location

Location

Shelf

bottom center, bottom center

Wall

right - south

Room

Wood room

Building

Mentzer Hall - Petrified Wood Room - Case #100B

Category

Permanent

Moved By

Catherine Boyd

Date

March 6, 2008

Location

Container

Right

Drawer

3rd Shelf

Shelf

Right

Cabinet

Case #100

Wall

South wall

Building

Mentzer Hall - Petrified Wood Room - Case #100B

Category

Permanent