GEM KNOWLEDGE · LABORATORY NOTES
Tanzberry (Red)
The precise inclusions of these pictured discs have not been established by the older report.
The name invites a closer look at what gives this Tanzanian quartz its color.
What the report found: The tested tumbled material is quartz containing abundant rounded red muscovite inclusions and some magnetite.
This assemblage differs from the Kazakhstan strawberry quartz specimen we tested, whose red color came from thin hematite blades. A shared color or trade name does not imply the same included mineral.
Compare the green material: Tanzberry (Green) · Green Strawberry Quartz (market name)
Related entries: Strawberry Quartz (Tanzania) · Red Aventurine (Tanzania) · Strawberry Quartz (Kazakhstan)
View the original report
Select a page to enlarge it. The text transcript below provides another way to read the findings.
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 (Tanzberry)
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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. Quartz.
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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. muscovite
Read the report as text
Transcript of the analytical report, including the figure descriptions and findings. The original pages above preserve the visual evidence and tables.
Analytical Result Report Sample id: 9035 (Tanzberry tumbled stones) Submitted by: K.Bitner Date submitted: May 29, 2020 Date completed: June 1, 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 (Tanzberry) Fig. 2: Energy dispersive spectrum of spot 1 in Fig. 1. Quartz. Fig. 3: Energy dispersive spectrum of spot 2 in Fig. 1. muscovite Fig. 4: Photomicrograph of inclusion of red muscovite. 3 mm across the field of view. Summary of findings: What a color! The matrix is quartz and lots of inclusions of rounded red muscovite and some magnetite grains as well. Trace elements and their concentrations are: iron, 1683 ppm, manganese, 892 ppm, titanium, 390 ppm and chromium, 69 ppm. Clearly, iron is the dominant chromophore and most likely, it is trivalent. Intervalence charge transfer reactions between iron and titanium and titanium and manganese likely play a role in bringing out this very attractive color. Direct current plasma spectrometry does test positive for a small amount of lithium, about 3 times above quantification limit, this most likely present mainly in the mica. So it is a slightly lithium-bearing muscovite. Date: June 1 ,2020 Signature
