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Michael Sommers' Photo Gallery

63rd Annual Show Poster

Copyright: © 2016 Houston Gem and Mineral Society      Photo ID: 784038     Uploaded by: Michael Sommers   View Count: 25   Approval status: User gallery    Type: Photo - 1024 x 697 pixels (0.7 Mpix)

R22-UHXPyrite : FeS2

Martin Marietta Materials Cement quarry, Midlothian, Ellis Co., Texas, USA

Dimensions: 3.3 cm x 3.5 cm x 0.7 cm
Largest Crystal Size: 8 mm

Several smaller (for the locality) crystals of pyrite on and around fossil shell material, with attached limestone matrix. Shell material is at least 2 species, possibly Inoceramus and Pseudoperna, with the Inoceramus remaining entirely calcite and the Pseudoperna mostly replaced by pyrite.
Copyright: © 2016 Michael G. Sommers      Photo ID: 783998     Uploaded by: Michael Sommers   View Count: 26   Approval status: Public galleries    Type: Photo - 3032 x 1964 pixels (6.0 Mpix)

1P1-689Gypsum : CaSO4·2H2O

Multiple photos available
Martin Marietta Materials Cement quarry, Midlothian, Ellis Co., Texas, USA

Dimensions: 5 cm x 3 cm x 2 cm
Largest Crystal Size: 9 mm

Pieces of massive, microcrystalline gypsum with bright red staining are fairly rare but can be found scattered in the quarry rubble. Some of these pieces contain larger subhedral crystals such as the two seen on the end of this piece (somewhat central in the image itself). According to the reference, gypsum can be found commonly in the bedding planes of the Eagle Ford shale, the unit stratigraphically below the Austin Chalk that is exposed within the quarry and occasionally dug into by the operation. Some gypsum is also reported within the basal phosphate pebble conglomerate, which is exposed in places within the quarry. I have not yet personally observed any in-place gypsum in 4 visits to the quarry.
Copyright: © 2016 Michael G. Sommers      Photo ID: 783995     Uploaded by: Michael Sommers   View Count: 29   Approval status: Public galleries    Type: Photo - 2736 x 3648 pixels (10.0 Mpix)

EWQ-WRQCalcite : CaCO3

Martin Marietta Materials Cement quarry, Midlothian, Ellis Co., Texas, USA

Field of View: 39 cm

End-on view (parallel to slip direction) of fault gouge block showing pocket of calcite crystals.
Copyright: © 2016 Michael G. Sommers      Photo ID: 783990     Uploaded by: Michael Sommers   View Count: 36   Approval status: Public galleries    Type: Photo - 3648 x 2736 pixels (10.0 Mpix)

EWQ-WRQCalcite : CaCO3

Martin Marietta Materials Cement quarry, Midlothian, Ellis Co., Texas, USA

Field of View: 15 cm

Closer view of the calcite slickensides. These particular slickensides are well-recrystallized and solid. Others on this piece are weak/friable, with plenty of buff colored clay/mud in between layers, and the sample as a whole is falling apart bit by bit, day by day.
Copyright: © 2016 Michael G. Sommers      Photo ID: 783987     Uploaded by: Michael Sommers   View Count: 24   Approval status: Public galleries    Type: Photo - 3648 x 2736 pixels (10.0 Mpix)

EWQ-WRQCalcite : CaCO3

Martin Marietta Materials Cement quarry, Midlothian, Ellis Co., Texas, USA

Dimensions: 39 cm x 27 cm x 11 cm

Full image of the block of recrystallized fault gouge and slickensides which the calcite crystals were found in.
Copyright: © 2016 Michael G. Sommers      Photo ID: 783986     Uploaded by: Michael Sommers   View Count: 34   Approval status: Public galleries    Type: Photo - 3648 x 2736 pixels (10.0 Mpix)

EWQ-WRQCalcite : CaCO3

Martin Marietta Materials Cement quarry, Midlothian, Ellis Co., Texas, USA

Field of View: 6 cm

Well-formed calcite crystals found in a pocket within recrystallized fault gouge/slickensides of the Austin Chalk in the quarry wall.
Copyright: © 2016 Michael G. Sommers      Photo ID: 783985     Uploaded by: Michael Sommers   View Count: 31   Approval status: Public galleries    Type: Photo - 3648 x 2736 pixels (10.0 Mpix)

UPW-JQJChalcedony (Var: Agate) : SiO2

Fruita, Mesa Co., Colorado, USA

Dimensions: 5 mm x 6 mm x 6 mm

Quartz (var chalcedony/agate) replaced gastropod from the Brushy Basin Member of the Jurassic Morrison Formation. Composite image from 6 stacked photos taken by a USB microscope. Note: these silicified gastropods are fairly well known in the literature, cf. Holt, E.L., 1942. Jour. Paleontology, v.16, n.4, pp.456-460.
Copyright: © 2016 Michael G. Sommers      Photo ID: 767769     Uploaded by: Michael Sommers   View Count: 137   Approval status: Public galleries    Type: Photo - 1561 x 1011 pixels (1.6 Mpix)
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