Pyrophyllite

Object/Artifact

-

Crater Rock Museum

Name/Title

Pyrophyllite

Entry/Object ID

78.63.372

Description

Crystal System: Monoclinic System Description: Common Name: Pyrophyllite Group Name:Silicates Location: Beresovskiy Mine, Yekaterinburg, Ural Mountains, Russia Chemistry: AlSi2O5OH Description: This specimen has multiple "leaf-like" structures with sprayed centers and a pearly consistancy. Color is a dark tan. PHYSICAL CHARACTERISTICS: Color is usually white, colorless, gray, yellow, pale green and/or blue. It can also be stained brown by iron oxides. • Luster is greasy to dull, but pearly on cleavage surfaces. • Transparency: Crystals are mostly translucent to opaque. • Crystal System is monoclinic; 2/m and triclinic; bar 1. • Crystal Habits include the typical fine grained, fibrous and lamellar masses, stellate aggregates and radiating spherules. Individual crystals are rare, but usually have a tabular subhedral or distorted form. • Cleavage is perfect in one direction. • Fracture is uneven or splintery. • Hardness is 1 - 1.5 (soft enough to be scratched by a fingernail). • Specific Gravity is approximately 2.65 - 2.85 (average). • Streak is white. • Other Characteristics: Cleavage sheets are flexible, but inelastic. A distinctive greasy feel to the touch. • Associated Minerals: are numerous, but a short list would include the micas, sericite, chlorite, graphite, quartz, albite, barite, gypsum, andalusite, kyanite, sillimanite, lazulite and epidote. • Notable Occurrences include Randolph, Guilford and Orange Counties, North Carolina, Chesterfield County, South Carolina; Mariposa County and San Bernardino County, California, Arizona and Graves Mountain, Georgia, USA as well as Belgium; China; Switzerland; Mexico; Minas Gerais, Brazil; Sweden; Ural Mountains, Russia; Korea and Japan. • Best Field Indicators are crystal habit, color, cleavage, softness, aluminum test and feel. Fracture: uneven Hardness: 2 Gypsum Luster: Vitreous Specific Gravity: 2.8 Streak: white

Collection

Delmar Smith Mineral Collection

Dimensions

Height

4-3/8 in

Width

1-7/8 in

Length

2-1/8 in

Dimension Notes

Dimension taken at widest points

Location

Location

Display Case

FS-11

Room

Frieda Smith Hall

Building

Crater Rock Museum

Category

Permanent

Moved By

Ian Cunningham

Date

December 27, 2023