GEM KNOWLEDGE · LABORATORY NOTES
Rhodonite from Peru
A pink and dark patterned specimen from Peru, analyzed to distinguish its mineral components.
Tested specimen: 8115 (Peru egg) · Report completed: April 14, 2020
Key finding: Both the pastel and brighter pink portions were identified as rhodonite with some calcium substitution and very little iron substitution. The dark material was identified at least in part as the manganese sulfide alabandite, called “alabandine” in the report.
What the report means
This entry applies to the tested Peruvian specimen. Other rhodonite localities and color combinations should be considered separately.
View the original test results
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Mineral identification is specific to the sample analyzed. The full report pages preserve the laboratory's wording and limitations.
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 photomicrograph of area 1 in sample 8115.
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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. (rhodonite)
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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. (alabandine)
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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 3 in Fig. 1. (rhodonite)
Read the report as text
This transcription makes the laboratory findings, figure captions, and table values available without opening the page images. Refer to the original images above for visual details.
Laboratory report
Analytical Result Report Sample id: 8115 Peru egg Submitted by: Kathreen Bitner Date submitted: April 10, 2020 Date completed: April 14, 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 attacement with 35kv potental in conjunction with the EDS system Fig 1: Backscattered electron photomicrograph of area 1 in sample 8115. Fig. 2: Energy dispersive spectrum of spot 1 in Fig. 1. (rhodonite) Fig. 3: Energy dispersive spectrum of spot 2 in Fig. 1. (alabandine) Fig. 4: Energy dispersive spectrum of spot 3 in Fig. 1. (rhodonite) Summary of findings: This is an interesting piece! Both the pastel pink and the brighter pink are rhodonite with some Ca substitution but very little iron substitution, thus the clean pink colors. The dark material is at least in part a manganese sulfide, alabandine! Alabandine is not that common. Date: 4-14-2020 Signature