Rhexoxylon (Seed Fern)

Object/Artifact

-

Crater Rock Museum

Name/Title

Rhexoxylon (Seed Fern)

Entry/Object ID

05.58.202

Description

Chemical Composition: Si O2 Crystal System: Hexagonal Description: Family: Coniferea Genus: Rhexoxylon Species: Africanus Common Name: Rhexoxylon Age: Middle Triassic Location data: Gokwe, Zimbabwe (Chimpanda) Description: Polished face shows colors of white, orange, black, brown, gray tones, growth rings are apparent. The slab is a complete round Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz 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 environment, 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: Medium 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.

Collection

Petrified Wood Collection

Acquisition

Accession

05.58

Source or Donor

Petrified Wood Collection

Acquisition Method

Donation

Other Names and Numbers

Other Number

Other Number: 2005.58.202

Dimensions

Width

10-1/2 in

Depth

1 in

Length

14-1/2 in

Dimension Notes

Dimension taken at widest points

Location

Location

Container

Left

Drawer

Bottom

Shelf

Left

Cabinet

Case #104

Wall

East Wall

Building

Mentzer Hall - Petrified Wood Room

Category

Permanent