Quartz in Basswood

Object/Artifact

-

Crater Rock Museum

Name/Title

Quartz in Basswood

Entry/Object ID

07.58.17

Description

Chemical Composition: Si O2 Crystal System: Hexagonal Description: Common name: Basswood Age: Oligocene to Early Miocene Location data: Little Butte Volcanic Series, Snowy Peak dig area near Sweethome Oregon USA Mehama Fm. Description: A one of a kind specimen half of a round log with huge quartz crystals clear in color filling in what was the log's central chamber. The cut faces are cream, brown, yellow, tan and white jasper & agate. **This oligocene specimen, part of a hollowed out trunk of basswood (Tilia) from Sweethome Oregon contaims large quartz crystals that grew in a void. When there is an opening in petrified wood, the growth of big crystals is not hampered by limited space; and so a later infusion of silica can result in the groth of large quartz crystals. voids may be caused by wood rot, desiccation cracks, or pressure fractures. These large, clear quartz crystals grew in the space inside the hollow log. Size: Diameter: 6 1/4" Length: 8 1/2" Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz Lithofacies: Siliceous tuffs Luster: Glassy Occurrence: Silicified wood, which is the fossilization and opalization of organic woody matter by the deposition of SiO2 in a anaerobic environment to prevent decay. This means that the wood must somehow be buried in an oxygen free enviroment, possibly in the silt-laden river or the bottom of a lake or buried by volcanic ash or related volcanic mudflow. The organic material in the wood is then replaced by silica (SiO2), other minerals determined its colors. 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

Other Number: 2007.58.17

Dimensions

Width

8-1/2 in

Length

6-1/4 in

Dimension Notes

Dimension taken at widest points

Location

Location

Container

Left

Drawer

Bottom

Shelf

Right

Cabinet

Case #101

Wall

South wall

Building

Mentzer Hall - Petrified Wood Room

Category

Permanent