GEM KNOWLEDGE · LABORATORY NOTES
Green Opal
© Soul Body GemsCollection photographs
© Soul Body Gems
© Soul Body Gems
© Soul Body Gems
© Soul Body Gems
© Soul Body GemsThese August 2025 collection views show forms of Green Opal from India. The laboratory findings below describe sample 1512, a green and brown heart; the images are not presented as documentation of that exact tested piece.
This green-and-brown opal came from a one-time find in India. According to Soul Body Gems sourcing history, the mine was subsequently paved over.
What our testing found
The specimen is predominantly silica, with minor aluminum and iron and smaller amounts of calcium, chromium and titanium. Optical examination and X-ray diffraction show poor, partial crystallinity. Both colors show an amorphous hump, and the green portion also shows the main peak of low quartz. The analyst identified the material as essentially opal undergoing incipient crystallization.
Collection background: India; one-time pocket find. The locality and mine history are supplied by Soul Body Gems.
Sample 1512, completed August 4, 2025. Findings apply to the specimen examined.
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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Diffraction scan: This scan helps identify crystalline minerals by comparing the measured pattern with reference patterns. The laboratory interpretation explains which minerals the comparison supports.
Laboratory figure caption: Fig. 3: X-ray diffraction scans of the green portion of the specimen on the left, and the brown portion on the right.
Read the complete report as text
Analytical Result Report
Sample id: 1512 (green and brown heart)
Submitted by: Soul Body Gems
Date completed: 8-4-2025
Operating conditions: A Bruker D2-Phaser was used in the study and operated at 30 kV and 10 mA.
In addition, a Bruker Titan X-rau fluorescence spectrometer was used and operated at 50, 25 and 10 kV.
Fig. 1: Photograph of the specimens. 5.5 cm maximum dimension.
Table 1: Major and minor elements in the specimen, in wt. %.
Green part
Brown part
Aluminum
2.12
1.24
Calcium
0.11
0.05
Chromium
0.20
0.08
Iron
0.54
0.98
Silicon
43.65
44.11
Titanium
0.07
nd
Fig. 2: Petrographic images of fine particles from the specimen. Plane polarized image on the left, crossed Nichols image on the right.
Fig. 3: X-ray diffraction scans of the green portion of the specimen on the left, and the brown portion on the right.
Summary of findings: This is an interesting specimen. Compositionally, it consists dominantly of silicon oxide (Table 1) with minor amounts of aluminum and iron and even less calcium, chromium and titanium. Optically, the material is partially crystalline as is evident by the birefringent areas in only parts of the particles (Fig. 2). X-ray diffraction confirms the poor crystallinity found optically (Fig. 3). The amorphous hump is distinct in both colors and in the green one, the major peak of low quartz was detected. The material is essentially opal that has undergone insipient crystallization. Often, cristobalite and/or tridymite is seen in opal that begins to crystallize and it is referred to as opal-CT.
The presence of chromium (Table 1) suggests some connection to mafic influence, maybe some basaltic volcanic ash may have played a role somewhere.
Date: 8-4-2025 Signature
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: 1512 (green and brown heart)
Submitted by: Soul Body Gems
Date completed: 8-4-2025
Operating conditions: A Bruker D2-Phaser was used in the study and operated at 30 kV and 10 mA.
In addition, a Bruker Titan X-rau fluorescence spectrometer was used and operated at 50, 25 and 10 kV.
Fig. 1: Photograph of the specimens. 5.5 cm maximum dimension.
Table 1: Major and minor elements in the specimen, in wt. %.
| Green part | Brown part | |
|---|---|---|
| Aluminum | 2.12 | 1.24 |
| Calcium | 0.11 | 0.05 |
| Chromium | 0.20 | 0.08 |
| Iron | 0.54 | 0.98 |
| Silicon | 43.65 | 44.11 |
| Titanium | 0.07 | nd |
Fig. 2: Petrographic images of fine particles from the specimen. Plane polarized image on the left, crossed Nichols image on the right.
Fig. 3: X-ray diffraction scans of the green portion of the specimen on the left, and the brown portion on the right.
Summary of findings: This is an interesting specimen. Compositionally, it consists dominantly of silicon oxide (Table 1) with minor amounts of aluminum and iron and even less calcium, chromium and titanium. Optically, the material is partially crystalline as is evident by the birefringent areas in only parts of the particles (Fig. 2). X-ray diffraction confirms the poor crystallinity found optically (Fig. 3). The amorphous hump is distinct in both colors and in the green one, the major peak of low quartz was detected. The material is essentially opal that has undergone insipient crystallization. Often, cristobalite and/or tridymite is seen in opal that begins to crystallize and it is referred to as opal-CT.
The presence of chromium (Table 1) suggests some connection to mafic influence, maybe some basaltic volcanic ash may have played a role somewhere.
Date: 8-4-2025 Signature