GEM KNOWLEDGE · LABORATORY NOTES
Iolite Sunstone (India)
Iolite Sunstone is the trade name used for this Indian material. The tested specimen is cordierite, also known as iolite, with tiny hematite inclusions and closely associated quartz.
What the testing found
- Chemical analysis confirms cordierite (iolite).
- Tiny hematite inclusions are visible in the photomicrograph.
- The cordierite is intimately associated with quartz.
- Some fractured areas contain resin filling.
Understanding the name
“Iolite Sunstone” is retained as the searchable trade name. The report identifies cordierite, hematite and quartz; it does not identify a separate sunstone feldspar in this specimen.
Locality: India, according to Soul Body Gems sourcing records. This entry is kept separate from the Tanzanian material.
View the original test results
Sample 9250. Select a page to enlarge it.
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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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 sample 19.
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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 spectral analysis of spot 1 in Fig. 2. (cordierite)
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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 spectral analysis of spot 2 in Fig. 2. (quartz with resin coating, note very low oxygen peak due to absorption)
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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. Left: Silicon-red, magnesium greenRight: Silicon-red, carbon-blue.
Read the complete report as text
Analytical Result Report
Sample id: 9250 (sample 19, iolite)
Submitted by: K. Bitner
Date submitted: March 27, 2021.
Date completed: May 8, 2021.
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 35kVpotental in conjunction with the EDS system.
Fig. 1: Photograph of the specimens #19, 6 cm maximum dimension.
Fig. 2: Backscattered electron image of sample 19.
Fig. 3: Energy dispersive spectral analysis of spot 1 in Fig. 2. (cordierite)
Fig. 4: Energy dispersive spectral analysis of spot 2 in Fig. 2. (quartz with resin coating, note very low oxygen peak due to absorption)
Fig. 5: X-ray maps. Left: Silicon-red, magnesium greenRight: Silicon-red, carbon-blue.
Fig. 6: Photomicrograph of specimen 19 showing hematite inclusions.
Table 1: Chemical composition in wt. % of the cordierite in sample 19.
Magnesium
7.33
Calcium
0.12
Aluminum
18.23
Silicon
23.83
Iron
1.65
Titanium
0.02
Summary of findings: This specimen (Fig. 1) is indeed cordierite (iolite) (Figs 2 and 3, Table 1). There are tiny hematite inclusions present (Fig. 6). The cordierite is intimately associated with quartz (Figs. 4 and 5). Some fractured areas were filled with a resin (Figs. 4 and 5 right). Cordierite is indeed brittle.
Date: May 8, 2021 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: 9250 (sample 19, iolite)
Submitted by: K. Bitner
Date submitted: March 27, 2021.
Date completed: May 8, 2021.
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 35kVpotental in conjunction with the EDS system.
Fig. 1: Photograph of the specimens #19, 6 cm maximum dimension.
Fig. 2: Backscattered electron image of sample 19.
Fig. 3: Energy dispersive spectral analysis of spot 1 in Fig. 2. (cordierite)
Fig. 4: Energy dispersive spectral analysis of spot 2 in Fig. 2. (quartz with resin coating, note very low oxygen peak due to absorption)
Fig. 5: X-ray maps. Left: Silicon-red, magnesium greenRight: Silicon-red, carbon-blue.
Fig. 6: Photomicrograph of specimen 19 showing hematite inclusions.
Table 1: Chemical composition in wt. % of the cordierite in sample 19.
| Magnesium | 7.33 |
|---|---|
| Calcium | 0.12 |
| Aluminum | 18.23 |
| Silicon | 23.83 |
| Iron | 1.65 |
| Titanium | 0.02 |
Summary of findings: This specimen (Fig. 1) is indeed cordierite (iolite) (Figs 2 and 3, Table 1). There are tiny hematite inclusions present (Fig. 6). The cordierite is intimately associated with quartz (Figs. 4 and 5). Some fractured areas were filled with a resin (Figs. 4 and 5 right). Cordierite is indeed brittle.
Date: May 8, 2021 Signature