Talc

Object/Artifact

-

Crater Rock Museum

Name/Title

Talc

Entry/Object ID

2013.1.21

Description

Chemical Composition: SiO2 Crystal System: Triclinic System Description: Common Name: Talc Chemistry: Mg3Si4O10(OH)2 Group: Silicates Location: Unknown Description: This specimen is a uniform block of fine grained material which is homogenic. It is a light tan with some darker areas. Physical Charateristics: •Color is olive green, yellow or golden, brown, or black. •Luster is greasy, waxy or silky. •Transparency crystals are translucent and masses are opaque. •Crystal System is variable, see above. •Crystal Habits: never in large individual crystals, usually compact masses or fibrous. Veins of viberous serpentine can be found inside of massive serpentine or other rocks. •Cleavage the varieties of crysotile have none, in lizardite and antigorite it is good in one direction. •Fracture is conchoidal in antigorite and lizardite and splintery in the crysotiles. •Hardness is 3 - 4.5 •Specific Gravity is 2.2 - 2.6 •Streak white •Associated Minerals include chromite, olivine, garnets, calcite, biotite and talc. •Other Characteristics: serpentine in the rough has a silky feel to the touch and fibers are very flexible. •Notable Occurances Val Antigorio, Italy; Russia; Rhodesia Switzerland; North Carolina, California, Rhode Island and Arizona, USA and Quebec, Canada. •Best Field Indicators softness, color, silky feel and luster, asbestos if present and its flexibility. Fracture: Conchoidal Hardness: 7 Quartz Luster: Pearly Rock Type: Sedimentary Specific Gravity: 2.68-2.72 Streak: White

Collection

RAGM Mineral Collection

Acquisition

Accession

2013.1

Source or Donor

Crater Rock Museum (Misc. donors)

Acquisition Method

Gift

Dimensions

Width

4-3/4 in

Depth

4 in

Length

4-1/4 in

Location

Location

Shelf

CS-E-4

Room

Curation Storage

Building

Crater Rock Museum

Category

Storage

Moved By

Jillian Mather Kettley

Date

March 6, 2024