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GEM KNOWLEDGE · LABORATORY NOTES

Rhodochrosite (China)

High-manganese rhodochrosite with only minor substitutions, associated with pyrite and quartz. A small phosphate phase was also observed.

Tested specimen: 1064 · Report completed: September 12, 2024

Supplied locality: China. Locality is supplied background, not independently established by the analysis.

What the report shows

The figure caption and summary differ in how they describe the accessory phosphate, so its exact species is not assigned here. This Chinese specimen is kept separate from our Peruvian and Argentinian rhodochrosite reports.

View the original report

Select any report page to enlarge it. A text transcript is available below.

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.

  • 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.

  • 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 (pyrite)

  • 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 (quartz)

  • 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.6: Backscattered electron image of another area of the specimen.

  • 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. 7: Energy dispersive spectrum of spot 1 in Fig. 6 (rhodochrosiite)

  • 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. 8: Energy dispersive spectrum of spot 2 in Fig. 2 (a phopspahte of mangaese and zinc, chlorine possibly as well but that could be an absorbed contaminant)

Read the report transcript

Analytical Result Report

Sample id: 1064 (#5, rhodochrosite from China)

Submitted by: Soul Body Gems

Date completed: 9-12-2024

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 specimen. Approximately 60 mm maximum dimension.

Fig.2: Backscattered electron image of an area of the specimen.

Fig. 3: Energy dispersive spectrum of spot 1 in Fig. 2 (pyrite)

Fig. 4: Energy dispersive spectrum of spot 2 in Fig. 2 (quartz)

Fig.6: Backscattered electron image of another area of the specimen.

Fig. 7: Energy dispersive spectrum of spot 1 in Fig. 6 (rhodochrosiite)

Fig. 8: Energy dispersive spectrum of spot 2 in Fig. 2 (a phopspahte of mangaese and zinc, chlorine possibly as well but that could be an absorbed contaminant)

Table 1: minor and trace elements in the rhodochrosite in wt. %.

Magnesium

0.31

Calcium

0.64

Iron

0.29

Zinc

0.05

Summary of findings: This specimen (Fig. 1) is very interesting, besides some associated pyrite (Figs. 2 and 3) and quartz (Figs. 2 and 4), the rhodochrosite is confirmed (Figs. 6 and 7). A small amount of a manganese-magnesium phosphate with high chlorine is also present. The chlorine maybe an absorbed contaminant. The rhodochrosite is a very high manganese rhodochrosite with only minor substitutions (Table 1)

Date: 9-12-2024 Signature

Report acknowledgment: These analytical results and report materials are the property of Soul Body Gems, Alexander Falster, and the Maine Mineral & Gem Museum. Any use or mention of these results requires full acknowledgment of all three.

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Results shown here apply to the specimens identified in the reports. A trade name or visual resemblance alone does not establish the composition of another piece.