American Bouquet

Submitted by Raven Mueller on Mon, 2014-07-07 09:25
Stone Type (Commercial): 
Physical Data
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Stone Type (Lithologic): 
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Specimen 2013:003

This sample is a plutonic rock dominated by mostly anhedral feldspar and a lesser amount of quartz. The crystalline structure is generally coarse but locally ranges to aplitic. Maximum crystal dimension is 9 mm (feldspar) and minimum is .<1 mm (quartz). Quartz grains are notably smaller on average than feldspar grains. Modal grain size is around 3 to 5 mm for feldspar and .15 to .75 mm for quartz. Feldspar twinning patterns include both tartan (microcline) and Carlsbad. Feldspar grain boundaries range from smooth curving to substantially consertal sutured. Quartz grain boundaries are generally consertal, this likely reflects stress induced recrystallization. Intergrowth textures include microperthitic involving multiple species of feldspar and granophyric with plagioclase intergrown with quartz. Accessory minerals include biotite, which is common at about 5 to 10 percent of slide area. A possible amphibole, based on cleavage, was likely present but is now significantly altered into iron oxides. No pyroxenes are visible in this slide. Opaques are also relatively rare and comprise less than 5 percent of slide area. There are slight signs of insipient weathering of feldspars with many grains presenting a dusty look. What is likely sericite is present in small patches (~10 µm) on some feldspar grains Rarely, grain boundaries and cracks in grains have begun to fill with reddish brown clay material (>20 µm in width).
7/7/2015 MP


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Specimen ID
2013-003 Polished facedownload image

Thin Sections

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Specimen ID Non-polarized Cross-polarized
2013-003 Specimen shown in non-polarized image Specimen shown in cross-polarized image


NOTE: Quarry locations are approximate.

American Bouquet Quarry
484th Ave.
57252 Milbank , South Dakota
United States
45° 11' 54.078" N, 96° 31' 1.74" W
South Dakota US

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