GEM KNOWLEDGE · LABORATORY NOTES
Purple Lace Agate
Mexican material sold under the names Purple Lace Agate, Amethyst Opal, and Matllali Lace Agate, with distinct purple and white silica-rich portions.
Sample: 1553 (#5 amethyst) · Completed: March 18, 2026.
Finding: Purple amethyst (low-quartz), with a white portion identified as opal-CT containing low-quartz, tridymite, and cristobalite.
Locality: Mexico, according to Soul Body Gems sourcing information.
Amethyst meeting opal-CT
The two colored portions are primarily silicon dioxide, but the white portion has more impurities. Its mixture of silica phases is characteristic of opal crystallizing from an amorphous state, described by the researcher as opal-CT.
All three directory names share this report and its findings.
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. 2: X-ray diffraction scan of the purple portion on the left and the white portion on the right.
Read the report findings and table as text
Sample 1553 (#5 amethyst), submitted by Soul Body Gems, completed March 18, 2026. A Bruker Titan X-ray fluorescence spectrometer operated at 10, 25, and 50 kV. A Bruker D2-Phaser X-ray diffractometer operated at 30 kV and 10 mA. Figure 1 shows a specimen of 4.5 cm maximum dimension, with a white-area close-up. Figure 2 compares purple and white diffraction scans.
| Element | Purple portion | White portion |
|---|---|---|
| Aluminum | 0.05 | 1.00 |
| Calcium | 0.1 | 0.45 |
| Iron | 0.15 | 0.10 |
| Silicon | 46.2 | 45.4 |
Summary: Both portions are essentially silicon dioxide, with more impurities in the white portion. Purple material is amethyst, low-quartz. White material is a mixture of low-quartz, tridymite, and cristobalite, typical of opal crystallizing from an amorphous state. This intermediate material is called opal-CT, often found near volcanic activity. The report ends with the March 18, 2026 date and 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: 1553 (#5 amethyst)
Submitted by: Soul Body Gems
Date completed: 3-18-2026
Operating conditions: A Bruker Titan X-ray fluorescence spectrometer was used and operated at 10, 25 and 50 kV.
A Bruker D2-Phaser X-ray diffractometer was also used and operated at 30 kV and 10 mA.
Fig. 1: Photograph of the specimen. 4.5 cm maximum dimension. Close-up oof the white area on the right.
Table 1: Major and minor elemental composition of the material, in wt. %.
| purple | white | |
|---|---|---|
| Aluminum | 0.05 | 1.00 |
| Calcium | 0.1 | 0.45 |
| Iron | 0.15 | 0.10 |
| Silicon | 46.2 | 45.4 |
Fig. 2: X-ray diffraction scan of the purple portion on the left and the white portion on the right.
Summary of findings: This is an interesting specimen (Fig. 1). The composition is essentially silicon dioxide for both, moore impurities are present in the white part. The purple portion is amethyst, low-quartz whereas the white portion is a mixture of low-quartz, tridymite and cristobalite which is typical for opal that is crystallizing from the amorphous state. This intermediate material is referred to as opal-CT. This is found often near volcanic activity.
Date: 3-18-2026 Signature