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Caramel Opal (Mexico)

“Caramel Opal” is the market name for this stone supplied as Mexican material. The ring was tested to investigate its composition; the report does not conclusively establish opal.

Finding: Sample 92924 (#1, ring), completed July 18, 2022, is silica-rich with markedly variable aluminum content and banding. The researcher considered a silica-replaced volcanic rock as one possibility. Small voids contained carbon-rich material, likely epoxy.

Identification remains open: The report calls the aluminum pattern unusual for opal. Its UV response was poor, but that alone does not settle identification. Refractive index could not be measured in the ring setting; crystallinity testing would require a small powder sample. The surficial metal analysis was consistent with sterling silver.

Origin and availability: Mexico is the supplied locality. Soul Body Gems has encountered this material as an obscure Mexican trade material; this specimen report does not establish that it occurs nowhere else. The report's signature date differs from its stated completion date; the original is shown as received.

View the original report

Select a page to enlarge it. 4 pages; findings are summarized in accessible text above.

Report images © Soul Body Gems, Alexander Falster and the Maine Mineral & Gem Museum. Please acknowledge all three when referring to these results. Findings apply to the specimen examined.

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 spectral analysis of spot 1 in Fig. 2 (High silica material with minor aluminum)

  • 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 spectral analysis of spot 2 in Fig. 2 (high silica material with elevated aluminum)

  • 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. 5: Energy dispersive spectral analysis of spot 3 in Fig. 2 (carbon-rich material – epoxy likely)

  • 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. 6 X-ray map of the area shown in Fig. 2: Silicon: yellow, aluminum: red.

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: 92924 (#1, ring)

Submitted by: K. Bitner

Date submitted: July 14, 2022.

Date completed: July 18, 2022.

Operating conditions: An AMRAY 1830 SEM operated at 25 kV acceleration potential, 26 mm working distance, 15 degrees sample tilt, coated with 250 Å carbon. Using the X-ray fluorescence attachment with 35 kV potential in conjunction with the EDS system.

Fig. 1: Photograph of the specimen. 4.5 cm maximum dimensions.

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

Fig. 3: Energy dispersive spectral analysis of spot 1 in Fig. 2 (High silica material with minor aluminum)

Fig. 4: Energy dispersive spectral analysis of spot 2 in Fig. 2 (high silica material with elevated aluminum)

Fig. 5: Energy dispersive spectral analysis of spot 3 in Fig. 2 (carbon-rich material – epoxy likely)

Fig. 6 X-ray map of the area shown in Fig. 2: Silicon: yellow, aluminum: red.

Table 1: Minor and trace element composition of the specimen. (in wt. %).

Laboratory data as recorded in the report
Element Reported value
Aluminum 0.2-2.97
Calcium 0.05-0.11
Iron 0.08-0.68
Manganese 0.01-0.04
Potassium 0.11-0.20
Sodium 0.10-0.21
Titanium 0.07-0.13

Summary of findings: This specimen (Fig. 1) is a silica-rich material (Figs. 2-4) with variable aluminum content (Figs. 2 and 4). Some small voids have been filled with an organic material, likely an epoxy compound (Figs. 2 And 5). The metal is surficially at least, Sterling silver with a little over 96 % silver and the rest mainly copper, I can check at greater depth.

Now comes the interesting part. The aluminum content and the distinct aluminum banding. The aluminum content is very variable (Table 1). A bit unusual for an opal. The appearance is more like some volcanic rock that flowed and then was replaced at least in part by silica. Alkalis are not present in large amounts (Table 1). UV fluorescence is poor, whereas many but not all opals show a fairly strong result. Unfortunately, the ring is sitting to high to measure the refractive index. Also, I could test for crystallinity but would need to remove a little powder of the stone, from the back where it would not be very noticeably.

Date: April 18, 2022 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.