GEM KNOWLEDGE · LABORATORY NOTES
Amethyst Velvet
An amethyst sphere sourced from Africa, with hollow tubes containing white material at exposed surfaces.
Sample: 1200 (amethyst sphere). Completed: December 21, 2024.
Finding: Quartz, variety amethyst. The white material in exposed tubes is a rare-earth oxide mixture interpreted as polishing residue.
Amethyst and the white material
The quartz contains typical iron and aluminum levels: 0.045 wt. % iron and 0.29 wt. % aluminum. Analysis of the white material found mainly cerium with smaller amounts of lanthanum, neodymium, and other light rare-earth elements.
The report interprets this as technical-grade cerium-oxide polishing material trapped in or caked over exposed hollow tubes. Another dozen filled tubes gave identical results. This interpretation concerns the exposed white filling, rather than identifying it as a natural inclusion.
Locality: Africa, according to Soul Body Gems sourcing notes; no specific country is supplied. The sphere measures approximately 7 cm.
View the original test results
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These results are the property of Soul Body Gems, Alexander Falster, and the Maine Mineral & Gem Museum. Any mention requires full acknowledgment.
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. (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. 4: Energy dispersive spectrum of spot 2 in Fig. 2. (rare earth oxide mix)
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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. 5: Backscattered electron image of another 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. 6: Energy dispersive spectrum of spot 1 in Fig. 2. (rare earth oxide mix)
Read the report as text
Analytical Result Report Sample id: 1200 (amethyst sphere) Submitted by: Soul Body Gems Date completed: 12-21-2024 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 specimens. 7 cm maximum dimensions. Smaller images show the hollow tubes filled with white material. Fig. 2: Backscattered electron image of an area of the specimen. Fig. 3: Energy dispersive spectrum of spot 1 in Fig. 2. (quartz) Fig. 4: Energy dispersive spectrum of spot 2 in Fig. 2. (rare earth oxide mix) Fig. 5: Backscattered electron image of another area of the specimen. Fig. 6: Energy dispersive spectrum of spot 1 in Fig. 2. (rare earth oxide mix) Summary of findings: This specimen (Fig. 1) is an interesting one! The quartz, var. amethyst is pretty normal (Figs. 2 and 3) and it contains the typical amount of iron and aluminum (0.045 wt. % iron, 0.29 wt. % aluminum). Hollow tubes run through part of the specimen (Fig. 1) and some are filled with white material. Where exposed at the surface (Figs. 2, 4, 5 and 6), the white material was shown to be an oxide of rare earth elements, especially cerium and lesser amounts of lanthanum, neodymium and other light rare earth elements. The exposed hollow tubes appear to have been filled with polishing material, technical grade cerium oxide with some of the other rare earth oxides is commonly used for this. Some calcium is also present (Figs. 2, 4, 5, and 6). Fig. 5 shows another one of these hollow tubes but here it is caked over the opening. In the spectra, silicon also shows up since the beam was scattered or penetrated through the white material. Another dozen of these filled tubes were checked with identical results. Date: 12-21-2024. Signature. Transcription note: Figure 6's reference to Fig. 2 is retained as printed.