GEM KNOWLEDGE · LABORATORY NOTES
Purple Muscovite
A purple bracelet submitted as lepidolite was identified as muscovite.
Sample 1154 · March 27, 2025.
Locality not supplied.
What the testing revealed
The report finds low fluorine and an aluminum-to-silicon ratio inconsistent with lepidolite. It identifies muscovite from a highly evolved granitic pegmatite.
A potassium-to-rubidium ratio of about 8 is interpreted as evidence of highly evolved melts. The finding applies to this tested bracelet and does not establish the identity of every purple mica.
Laboratory report
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.2: Backscattered electron image of an area of the specimen.
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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 1 in Fig. 2. (muscovite)
Read the complete report as text
Analytical Result Report
Sample id: 1154 (#4 lepidolite bracelet)
Submitted by: Soul Body Gems
Date completed: 3-27-2025
Operating conditions: An AMRAY 1830 SEM operated at 25 kV acceleration potential, 24 mm working distance, 0 degrees sample tilt, coated with 250 Å carbon, and also using the attached XRF unit operated at 30 kV.
Fig. 1: Photograph of the specimen.
Fig.2: Backscattered electron image of an area of the specimen.
Fig. 3: Energy dispersive spectrum of spot 1 in Fig. 2. (muscovite)
Summary of findings: This specimen (Fig. 1) is a very interesting specimen! It is not lepidolite but a muscovite! Fluorine is low and the ratio of aluminum to silicon is wrong. It is a muscovite from a highly evolved granitic pegmatite, the K/Rb ratio is about 8 which is very low and indicative of highly evolved melts.
Date: 3-27-2025 Signature
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: 1154 (#4 lepidolite bracelet)
Submitted by: Soul Body Gems
Date completed: 3-27-2025
Operating conditions: An AMRAY 1830 SEM operated at 25 kV acceleration potential, 24 mm working distance, 0 degrees sample tilt, coated with 250 Å carbon, and also using the attached XRF unit operated at 30 kV.
Fig. 1: Photograph of the specimen.
Fig.2: Backscattered electron image of an area of the specimen.
Fig. 3: Energy dispersive spectrum of spot 1 in Fig. 2. (muscovite)
Summary of findings: This specimen (Fig. 1) is a very interesting specimen! It is not lepidolite but a muscovite! Fluorine is low and the ratio of aluminum to silicon is wrong. It is a muscovite from a highly evolved granitic pegmatite, the K/Rb ratio is about 8 which is very low and indicative of highly evolved melts.
Date: 3-27-2025 Signature