GEM KNOWLEDGE · LABORATORY NOTES
Rainbow Dolomite (Trade Name)
Sold as “Rainbow Dolomite,” these colorful banded specimens were tested as sample 1220. The laboratory attributed their vivid colors to organic dyes and pigments. The report did not establish that the underlying material is the mineral dolomite.
Sample 1220 · March 5, 2025
What the testing found
Analysis found abundant carbon compounds with calcium, magnesium, silicon, aluminum and chloride. The analyst found none of the usual inorganic color-producing elements listed in the report and attributed the vivid bands to organic dyes and pigments. “Rainbow Dolomite” is the market name used here; the report did not confirm the mineral identity of the underlying material.
View the original test results
Select a page to enlarge it. All 3 pages are included.
These results are the property of Soul Body Gems, Alexander Falster and the Maine Mineral & Gem Museum. Any use or mention requires full acknowledgment of all three.
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 left specimen in Fig. 1.
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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. (mostly carbon-based with calcium, magnesium, silicon and chloride)
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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 (mostly carbon-based with calcium, magnesium, silicon and chloride).
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Element map: This map shows where the named elements occur within the analyzed area. Its colors represent the laboratory’s selected element channels, rather than the specimen’s visible colors. The caption below preserves any color key or distribution noted by the laboratory.
Laboratory figure caption: Fig. 5: X-ray maps of an area of the specimen. On top a screen shot of multiple elements, at the bottem, red is carbon, yellow is aluminum.
Read the complete report as text
Analytical Result Report
Sample id: 1220 (#3 colorful!)
Submitted by: Soul Body Gems
Date completed: 3-5-2025
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.
A Bruker D2 Phase X-ray diffractometer was also used in the study and operated at 30 kV and 10 mA.
Fig. 1: Photograph of the specimens. 4 cm maximum dimension.
Fig.2: Backscattered electron image of an area of the left specimen in Fig. 1.
Fig. 3: Energy dispersive spectrum of spot 1 in Fig. 2. (mostly carbon-based with calcium, magnesium, silicon and chloride)
Fig. 4: Energy dispersive spectrum of spot 2 in Fig. 2 (mostly carbon-based with calcium, magnesium, silicon and chloride).
Fig. 5: X-ray maps of an area of the specimen. On top a screen shot of multiple elements, at the bottem, red is carbon, yellow is aluminum.
Summary of findings: These specimens (Fig. 1) are very beautiful! Interestingly, the composition is very uniform, inorganic components are calcium, magnesium, silicon, aluminum, chloride. With a very high concentration of carbon compounds (Figs. 2-5). Aluminum is a little spotty and it may be that aluminum oxide was used to polish the specimens. None of the typical chromophoric elements such as copper, iron, manganese, chromium, vanadium, titanium etc., are present! Note in Figs. 2 and 3, at the low energy end to the left, oxygen overlaps with the Lalpha lines of those elements but the Kalpha lines to the right are missing. All the beautiful colors are made by organic dyes and pigments! I was looking forward to see some really great X-ray maps!
Date: 3-5-2025 Signature