Paulina Pink Limb Cast

Object/Artifact

-

Crater Rock Museum

Name/Title

Paulina Pink Limb Cast

Entry/Object ID

78.61.99 (b)

Description

Assemblage Zone: sedimentary Chemical Composition: Si O2 Crystal System: Hexagonal Description: Age: Mid-Miocene Location data: Crooked River, Central Oregon John Day Fm. Description: (2) Limbcast - Polished ends show grey and pinkish grey agate, outer case is pink & beiges Size: Diameter: 1" Length: 21/8" 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 Collection

Other Names and Numbers

Other Number

Other Number: 1978.61.99B

Dimensions

Dimension Notes

Dimension taken at widest points

Location

Location

Shelf

CS-F-1

Room

Curation Storage

Building

Crater Rock Museum

Category

Storage

Moved By

Curator

Date

February 21, 2024