London Pegmatite Specimens

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Schorl

replaced by Lepidolite - #DL63088

Details
Data
Provenance
Resources

Locality: Anderson pegmatites, Homestead claim, White Picacho Mining dist., Yavapai Co., Arizona, United States
Formula: NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
Availability: Sold
Size: 11 x 7 x 4 cm - Cabinet
Tagged: pegmatite mineral

A former Schorl crystal completely replaced by very fine, dark green Lepidolite.

Schorl

Formula: NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
Crystal System: Trigonal
Crystal Habit: Acicular, Prismatic, Striated
Cleavage: Indistinct, None, None
Luster: Vitreous (Glassy)
Color: black, brownish black, greenish black, bluish black
Streak: brown
Class: Trigonal - Ditrigonal Pyramidal
Fracture: Brittle - Conchoidal
Hardness: 7.5

Collection: Dr. David London Collection

Mineralpedia: View Schorl
On Dakota Matrix: Previously Sold Schorl
On Dakota Matrix: Other Available Schorl
WebMineral: View Schorl
Mindat: View Schorl

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Schorl

intergrowth with Quartz - #DL63837

Details
Data
Provenance
Resources

Locality: Midnight Owl mine, Yavapai Co., Arizona, United States
Formula: NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
Availability: Sold
Size: 11 x 8 x 5 cm - Cabinet
Tagged: pegmatite mineral
Special Info: Illustrated in London's book "Pegmatites"

This specimen is illustrated on page 185, Fig. 12-6a of London's book called "Pegmatites".

This specimen of Schorl tourmaline exhibits the intergrowth with Quartz much like Quartz -Microcline graphite granite. One of the interesting features of Schorl in pegmatites is the nucleation of tourmaline along the contact zone of pegmatite with the wall-rock. At this contact tourmaline begins to grow rapidly toward the center of the pegmatite and perpendicular to the wall. Tourmaline is a cyclosilicate and crystallizes like a spiral outward from that original point of nucleation with the wall. All crystals of Schorl will compete for the boron in solution and rapid crystallization produces divergent crystals.

Schorl

Formula: NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄
Crystal System: Trigonal
Crystal Habit: Acicular, Prismatic, Striated
Cleavage: Indistinct, None, None
Luster: Vitreous (Glassy)
Color: black, brownish black, greenish black, bluish black
Streak: brown
Class: Trigonal - Ditrigonal Pyramidal
Fracture: Brittle - Conchoidal
Hardness: 7.5

Collection: Dr. David London Collection
Special Info: Illustrated in London's book "Pegmatites"

Mineralpedia: View Schorl
On Dakota Matrix: Previously Sold Schorl
On Dakota Matrix: Other Available Schorl
WebMineral: View Schorl
Mindat: View Schorl

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Simpsonite

in Albite with Microlite - #DL63804

Details
Data
Provenance
Resources

Locality: Tanco pegmatite, Bernic Lake, Manitoba, Canada
Formula: Al₄Ta₃O₁₃(OH)
Availability: Sold
Size: 13 x 11 x 3.5 cm - Cabinet
Tagged: pegmatite mineral , tantalum
Special Info: Illustrated in London's book "Pegmatites"

Banded Aplite composed of reddish grains of Microlite, Albite and Simpsonite. The Simpsonite glows bright blue under SW FL. Illustrated on page 74, Fig. 4-18g.