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John A. Jaszczak's Photo Gallery

2VY-7YEScapolite

Morogoro Region, Tanzania

Dimensions: 1.7 cm x 1.3 cm x 2.1 cm

Prismatic, chatoyant, yellow-orange scapolite-group crystal with orange-red sectors. Raman spectroscopy (633 nm laser) suggests marialite, but this specimen's chemistry has not yet been analyzed.
Copyright: © John A. Jaszczak      Photo ID: 858772     Uploaded by: John A. Jaszczak   View Count: 15   Approval status: Public galleries    Type: Photo - 960 x 720 pixels (0.7 Mpix)

9QA-WAYQuartz : SiO2, Copper : Cu

Laurium Mine, Laurium, Houghton Co., Michigan, USA

Largest Crystal Size: 0.9 mm

Quartz crystal partly enclosed in copper in a vug in epidotized basalt. Collected by Tom Rosemeyer.
Copyright: © John A. Jaszczak      Photo ID: 858021     Uploaded by: John A. Jaszczak   View Count: 16   Approval status: Public galleries    Type: Photo - 2908 x 1939 pixels (5.6 Mpix)

X09-4KJErniggliite : Tl2SnAs2S6, Dolomite : CaMg(CO3)2

Lengenbach Quarry, Fäld, Binn Valley, Wallis, Switzerland

Dimensions: 0.10 mm x 0.07 mm

An extremely small but well-formed erniggliite crystal on dolomite. Also associated but not shown here are jentschite, hatchite, rutile, trechmannite, and realgar. EDS analysis by P. Roth.
Copyright: © John A. Jaszczak      Photo ID: 856328     Uploaded by: John A. Jaszczak   View Count: 16   Approval status: Public galleries    Type: Photo - 1788 x 1192 pixels (2.1 Mpix)

X09-4KJJentschite : TlPbAs2SbS6, Dolomite : CaMg(CO3)2

Lengenbach Quarry, Fäld, Binn Valley, Wallis, Switzerland

Field of View: 1.07 mm

Dark red bladed crystals of jentschite associated with dolomite, and also not shown are ernigglite, rutile, trechmannite, hutchinsonite, and tennantite. Note the oblique termination relative to the long axis. Formerly in the collection of P. Roth who verified species with EDS.
Copyright: © John A. Jaszczak      Photo ID: 856046     Uploaded by: John A. Jaszczak   View Count: 40   Approval status: Public galleries    Type: Photo - 3872 x 2581 pixels (10.0 Mpix)

L1F-2C5Fluorapatite : Ca5(PO4)3F, Diopside : CaMgSi2O6, Grossular (Var: Tsavorite) : Ca3Al2(SiO4)3, Graphite : C, Pyrite : FeS2

Multiple photos available
Merelani Hills, Lelatema Mts, Simanjiro District, Manyara Region, Tanzania

Largest Crystal Size: 3.7 mm

Steeply terminated blue fluorapatite crystal associated with almost colorless diopside, pale green tsavorite, and tabular graphite crystals. These are perched on a large (15 cm) sample of graphite that is also associate with white calcite crystals. The calcite and tsavorite crystals fluoresce pink and orange, respectively, in longwave UV light.
Copyright: © John A. Jaszczak      Photo ID: 851710     Uploaded by: John A. Jaszczak   View Count: 18   Approval status: Public galleries    Type: Photo - 5184 x 3456 pixels (17.9 Mpix)

G2J-52DManganite : Mn3+O(OH), Albite : Na(AlSi3O8), Epidote : {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Central Mine, Central, Keweenaw Co., Michigan, USA

Field of View: 6.7 mm

"Exceptional elongated micro crystals of manganite contained in a 4.3 mm vug of altered vesicular felsite. The felsite cobble was a clast in the Calumet and Hecla Conglomerate that was mineralized adjacent to the Central mine fissure vein and mined in the 1880's. The manganite crystals are perched on a matrix of crystallized albite, epidote, and a few hairs of tremolite[?]. The specimen was collected at the Central mine, #2 shaft, Central, Keweenaw County, Michigan by Tom Rosemeyer on 2 July 2017. About 30 micro groups were trimmed out of the cobble and are arguably the finest manganite crystals that have been found in the Michigan Copper District." --Tom Rosemeyer
Copyright: © John A. Jaszczak      Photo ID: 849403     Uploaded by: John A. Jaszczak   View Count: 20   Approval status: Public galleries    Type: Photo - 5184 x 3456 pixels (17.9 Mpix)

KQ5-446Copper : Cu, Prehnite : Ca2Al2Si3O10(OH)2

Cliff mine, Phoenix, Keweenaw Co., Michigan, USA

Field of View: 2.9 mm

A lustrous group of micro complex copper crystals contained in a 2.4 mm vug of a crystallized prehnite vein 7-mm wide. The specimen was collected by Tom Rosemeyer on 19 August 2017 at the Avery shaft mine dump, Cliff mine, Keweenaw County, Michigan. The specimen has not been cleaned in any manner except for a breath of air to blow off dust particles from trimming the specimen.
Copyright: © John A. Jaszczak      Photo ID: 847986     Uploaded by: John A. Jaszczak   View Count: 59   Approval status: Public galleries    Type: Photo - 2500 x 1667 pixels (4.2 Mpix)

TDH-Y4KCarminite : PbFe3+2(AsO4)2(OH)2, Calcite : CaCO3, Limonite : (Fe,O,OH,H2O)

Ojuela Mine, Mapimí, Mun. de Mapimí, Durango, Mexico

Dimensions: 5 cm x 3.5 cm x 3 cm

Micro acicular red carminite crystals partly coated by transparent acute rhombohedral calcite crystals, on limonite. Possibly from the material collected in 1983 from La Ciguena vein and rescued by Mike New. (Acquired in my collection in 1985.)
Copyright: © John A. Jaszczak      Photo ID: 828120     Uploaded by: John A. Jaszczak   View Count: 19   Approval status: Public galleries    Type: Photo - 3000 x 2068 pixels (6.2 Mpix)

31G-9UXGraphite : C

Multiple photos available
Olmstedville, Minerva Township, Essex Co., New York, USA

Largest Crystal Size: 1 μm

Euhedral graphite crystal perched on the edge of a larger graphite crystal that is actually a columnar graphite overgrowth (8 micron) on yet a larger (1.9 mm wide) graphite host crystal. These graphite crystals with overgrowths were dissolved from friable calcite marble from a roadcut north of Olmstedville. The image is a composite of 2 stacked images from a Hitachi field emission scanning electron microscope (S-4700).
Copyright: © John A. Jaszczak      Photo ID: 828117     Uploaded by: John A. Jaszczak   View Count: 161   Approval status: Featured    Type: Photo - 1280 x 887 pixels (1.1 Mpix)

WPV-4JHCalcite : CaCO3, Dolomite : CaMg(CO3)2

Smith Quarry, Black Rock, Lawrence County Zinc District, Lawrence Co., Arkansas, USA

Largest Crystal Size: 8 cm

A pair of twinned Calcite crystals from Smith Quarry, Black Rock, Lawrence Co., Arkansas. The crystals also show faint phantoms, and the large crystal has a movable gas bubble in a small fluid-filled channel on the back side of the crystal.
Copyright: © John A. Jaszczak      Photo ID: 820769     Uploaded by: John A. Jaszczak   View Count: 47   Approval status: Public galleries    Type: Photo - 3500 x 2333 pixels (8.2 Mpix)
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