Dendritic Agate

Object/Artifact

-

Crater Rock Museum

Name/Title

Dendritic Agate

Entry/Object ID

1988.6.189

Description

Chemical Composition: SiO2 (MnO2) Crystal System: Triclinic System Description: Common Name: Quartz var.agate (dendritic) Chemistry: SiO2 Class: Silicates Location: COPCO, Southern Oregon Description: Flat back with convex polished face. Translucent creamy white with a fracture seperating a blue-gray side. (1) black dendritic structure. Physical Characteristics: Dendritic agate is a whitish-gray or colorless chalcedony with tree- or fern-like markings known as dendrites. The variety name agate is used for this gem even though it does not exhibit the banding typical of agate.The dendrites in dendritic agate are iron or manganese inclusions, usually brown or black in color. Though they appear organic due to their fern-like structure, they are actually inorganic; they are formed at fine fracture surfaces through crystallization of weathered solutions of neighboring rock. Fracture: Conchoidal Hardness: 7 Quartz Luster: Glassy Occurrence: Quartz is an essential constituent of granite and other felsic igneous rocks. It is very common in sedimentary rocks such as sandstone and shale and is also present in variable amounts as an accessory mineral in most carbonate rocks. It is also a common constituent of schist, gneiss, quartzite and other metamorphic rocks. Because of its resistance to weathering it is very common in stream sediments and in residual soils. Rock Type: Sedimentary Specific Gravity: 2.65 Streak: White Variety: Quartz is the most common mineral on the face of the Earth. It is found in nearly every geological environment and is at least a component of almost every rock type. It frequently is the primary mineral, >98%. It is also the most varied in terms of varieties, colors and forms. This variety comes about because of the abundance and widespread distribution of quartz. A collector could easily have hundreds of quartz specimens and not have two that are the same due to the many broad catagories.

Collection

Boyd Kline

Acquisition

Accession

1988.6

Source or Donor

Boyd Kline

Acquisition Method

Gift

Dimensions

Width

1 in

Depth

11/16 in

Length

1-11/16 in

Location

Location

Container

Left

Drawer

Top Shelf

Shelf

Left, Left

Wall

North

Room

Freida Smith Hall

Building

Freida Smith Hall:

Category

Permanent

Moved By

Steve Miller

Date

August 16, 2011

Location

Container

Left

Drawer

4th Row / Bottom

Shelf

Right, Right

Wall

East

Building

Founders Room

Category

Permanent

Moved By

Steve Miller

Date

August 16, 2011

Location

Cabinet

Case# 10

Building

Menzter Hall

Category

Permanent