GEM KNOWLEDGE · LABORATORY NOTES
Sodalite Syenite
A specimen sold as hackmanite was examined as a whole rock, revealing a sodalite-bearing nepheline syenite.
Tested specimen: 92838 (#8) · Report completed: September 7, 2021
Key finding: The report identifies a silica-deficient rock, sodalite syenite, containing nepheline, sodalite, a kalsilite-nepheline solid solution, and albite.
What the report means
The report characterizes the submitted rock and its mineral constituents. It does not identify the specimen as hackmanite. Read the companion Hackmanite market-name entry for why that distinction matters.
View the original test results
Both entries refer to this same tested specimen and the same analytical report. Select a page to enlarge it.
The report applies to this individual specimen. Its wording is preserved in the images.
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 images 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. (nepheline)
-
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 3 in Fig. 2. (sodalite)
-
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 5 in Fig. 2. (kalsilite/sodalite solid solution)
-
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. 6: Energy dispersive spectral analysis of spot 7in Fig. 2. (albite)
-
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. 7: X-ray map of Fig. 2. Left: sodium: red, potassium: green. Right: sodium: red, potassium: green, chlorine: yellow
Read the report as text
This transcription makes the laboratory findings, figure captions, and table values available without opening the page images. Refer to the original images above for visual details.
Laboratory report
Analytical Result Report Sample id: 92838 (#8) Submitted by: K. Bitner Date submitted: Aug.2, 2021. Date completed: Sept. 7, 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 35 kV potential in conjunction with the EDS system. Fig. 1: Photograph of the specimen. 5.8 cm maximum dimension. Fig. 2: Backscattered electron images of the specimen. Fig. 3: Energy dispersive spectral analysis of spot 1 in Fig. 2. (nepheline) Fig. 4: Energy dispersive spectral analysis of spot 3 in Fig. 2. (sodalite) Fig. 5: Energy dispersive spectral analysis of spot 5 in Fig. 2. (kalsilite/sodalite solid solution) Fig. 6: Energy dispersive spectral analysis of spot 7in Fig. 2. (albite) Fig. 7: X-ray map of Fig. 2. Left: sodium: red, potassium: green. Right: sodium: red, potassium: green, chlorine: yellow Table 1: Minor and trace element composition of the specimen. (in wt. %). Iron 0.05 Chlorine 2.62 Calcium 0.54 Strontium 0.02 Manganese 0.01 Summary of findings: This specimen (Fig. 1) is a very interesting specimen: It is silica-deficient rock type called sodalite syenite, a sodalite-bearing nepheline syenite. Note the high chlorine content (Fig. 4) which also is evident in Table 1. These rocks are very rare and only occur in continental areas where crustal thinning occurs, just before rifting occurs. This specimen contains nepheline (Figs. 2 and 3), sodalite (Figs. 2 and 4), kalsilite-nepheline solid solution (Figs. 2 and 5) and albite (Figs. 2 and 6. There is some hint of foliation present (Fugs 2 and 7), this can happen already during intrusion but could also appear later during tectonic events. Date: Sept. 7, 2021 Signature




