Agate

Object/Artifact

-

Crater Rock Museum

Name/Title

Agate

Entry/Object ID

78.59.664

Description

Chemical Composition: SiO2 Crystal System: Triclinic System Description: Common Name: Agate Chemistry: SiO2 , Silicon dioxide Class: Class: Silicates Location: Brazil Description: Thick slice of agate. Polished side shows open crystalline hole in pinkish cream, surrounded by fortified agate in pinkish cream, crystalline white, blue green, olive, and black, with cream and brown at outer edge. Two crystalline holes seen along edge. 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. Quartz occurs in hydrothermal veins as gangue along with ore minerals. Large crystals of quartz are found in pegmatites. Well-formed crystals may reach several meters in length and weigh hundreds of kilograms. 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

Delmar Smith Mineral Collection

Acquisition

Accession

78.59

Source or Donor

Delmar Smith Agate Collection

Acquisition Method

Gift

Dimensions

Width

9-1/2 in

Depth

7/8 in

Length

7-3/8 in

Dimension Notes

Dimension taken at widest points

Location

Location

Shelf

CS-H-2

Room

Curation Storage

Building

Crater Rock Museum

Category

Storage

Moved By

Jillian Mather Kettley

Date

February 8, 2024