Royal Purple

Submitted by Raven Mueller on Tue, 2014-07-08 10:17
Stone Type (Commercial): 
Physical Data
Munsell Color(s): 
Stone Type (Lithologic): 
Grain Size: 
Very Fine
Petrographic Description: 

Specimen: 2014-011

This specimen is a red slate. The color of the specimen suggests the presence of hematite and limonite. Owning to the aphanitic nature of the material, many of the constituent minerals in this specimen cannot be identified through microscopy. Quartz/feldspar grains are common with a maximum dimension of .2 mm, most are smaller. Various species of mica presumably form the majority of the specimen’s fabric, but these are generally too small to be individually perceived. Identifiable crystals of mica are.2 mm and less in length and show some orientation preference. Carbonate minerals are not apparent in this slide. Relict sedimentary features are minimally visible on macro-inspection of the slide in the form of faint banding. These are difficult to discern under the microscope, but are suggested by the prevalence of opaque and red hydroxide minerals and differences in the translucency of the aphanitic component. Overall the lack of more significant grain elongation and orientation prevalence indicates very low grade metamorphism. This may be due to the slide’s orientation, which is perpendicular to the likely direction of maximum tectonic stress.

7/16/14 MP


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Specimen ID
2014-011 Image of specimen in dry conditions. Finish: Natural cleftdownload image Close-up image of specimen in dry conditions. Finish: Natural cleftdownload image

Thin Sections

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Specimen ID Non-polarized Cross-polarized
2014-011 Specimen shown in non-polarized image Specimen shown in cross-polarized image


No quarry information available for this stone.

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