GEM KNOWLEDGE · LABORATORY NOTES
Mystery Stone 6 (Afghan Tower)
A purple-and-white tower supplied from Afghanistan.
Finding: Sample 9147, completed July 16, 2020, contains clean calcite in the white region and quartz, partly amethyst, in the purplish region.
The researcher suggested a possible hydrothermal vein environment. The two colors represent different minerals in this tested tower.
View the original report
Select a page to enlarge it. 2 pages; findings are summarized in accessible text above.
Report images © Soul Body Gems, Alexander Falster and the Maine Mineral & Gem Museum. Please acknowledge all three when referring to these results. Findings apply to the specimen examined.
Understanding the report figures
Use this guide alongside the written findings and the original report transcript. It explains the purpose of each analytical figure and preserves the laboratory’s own figure labels. The interpretations apply to the tested specimen; signals alone do not establish the identity of every similar-looking stone.
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Electron microscope image: This view shows small-scale regions selected for analysis. Its brightness contrast helps distinguish regions with different compositions; it is not a photograph of their natural colors. Numbered spots connect this view to the analyses listed in the report.
Laboratory figure caption: Fig. 1: Backscattered electron image (purple/white tower Afghan)
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Elemental spectrum: The peaks record characteristic X-ray signals from elements in the analyzed spot or area. This is an analysis of that location, not automatically of the entire specimen. Any mineral identification or uncertainty named in the laboratory caption is retained below.
Laboratory figure caption: Fig. 2: Energy dispersive spectrum of spot 1 in Fig. 1. (calcite).
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Elemental spectrum: The peaks record characteristic X-ray signals from elements in the analyzed spot or area. This is an analysis of that location, not automatically of the entire specimen. Any mineral identification or uncertainty named in the laboratory caption is retained below.
Laboratory figure caption: Fig. 3: Energy dispersive spectrum of spot 2 in Fig. 1. (quartz).
Read the original laboratory report as text
The following text and tables are transcribed from the original laboratory document. Figure captions identify the report images; the laboratory interpretations and limitations are preserved.
Laboratory report 1
Analytical Result Report
Sample id: 9147 (#4 purple/white tower Afghan)
Submitted by: K. Bitner
Date submitted: July 13, 2020
Date completed: July 16, 2020
Operating conditions: JEOL JSM-6400 operated at 25 kV acceleration potential, 15 mm working distance, 15 degrees sample tilt, coated with 250 Å carbon. Using the X-ray fluorescence attachment with 35kv potental in conjunction with the EDS system.
Fig. 1: Backscattered electron image (purple/white tower Afghan)
Fig. 2: Energy dispersive spectrum of spot 1 in Fig. 1. (calcite).
Fig. 3: Energy dispersive spectrum of spot 2 in Fig. 1. (quartz).
Summary of findings: This is a specimen that surprised me. The white portion is very clean calcite (Figs. 1 and 2) (240 ppm iron, 50 ppm manganese) whereas the purplish portion is quartz (Figs. and 3), essentially amethyst in part. The iron content is a little higher (400 ppm) and no manganese detectable. This material could have come from a hydrothermal vein environment.
Date: July 16 ,2020 Signature