GEM KNOWLEDGE · LABORATORY NOTES
Hackmanite
A bracelet identified as sodalite-group material, described in the report as essentially hackmanite.
Sample: 10679 (#9 bracelet). Completed: August 30, 2024.
Finding: Sodalite-group beads, essentially hackmanite, containing some very iron-poor phlogopite inclusions.
The researcher notes that sodalite-group species form in silica-undersaturated rock types, such as nepheline syenite. The report does not supply a locality or document a tenebrescence test.
This is a separate specimen from the material listed elsewhere as “Hackmanite (Not).” The results here describe this bracelet.
Our collection: Soul Body Gems confirms that the Hackmanite pendant collection uses the same material as the bracelet tested in the report below.
Hackmanite and the sodalite family
Hackmanite is a variety of sodalite associated with reversible changes in body colour. Sodalite is a sodium aluminium silicate with a cage-like framework, and it typically occurs in silica-undersaturated rocks such as nepheline syenite and phonolite. A material can contain sodalite without showing the particular optical behaviour that makes hackmanite so engaging. This is why mineral identity, the properties observed in a specimen and the name used in commerce all deserve attention.
Tenebrescence: colour that remembers light
Tenebrescence is a reversible change in the colour of a material after exposure to suitable radiation. A pale piece of hackmanite can become pink or purple under ultraviolet light, then gradually return toward its earlier appearance under other lighting conditions. The effect is not simply the colour of light shining on the stone. Researchers at the University of Turku explain how movement of atoms within the mineral's cage structure can accompany these repeatable changes while the overall framework remains intact. The material's internal structure changes how it absorbs visible light.
Colour change and fluorescence
Two observations should be recorded separately: whether a stone emits a visible glow while the UV lamp is on, and whether its body colour has changed when viewed afterward in ordinary light. The first is fluorescence; the second can be tenebrescence. A photograph taken only under UV light cannot document both effects at once. For an informative comparison, photograph the piece in ordinary light before exposure, during UV illumination, and again in ordinary light afterward. Keep camera exposure and white balance consistent where possible, because automatic settings can exaggerate differences.
Why scientists are interested
Hackmanite-inspired materials are being investigated for radiation sensing. The University of Turku's Intelligent Materials Chemistry group studies materials whose colour response can relate to ultraviolet or X-ray exposure. These applications require calibrated materials and controlled measurements; a jewellery stone should not be treated as a ready-made radiation meter. The research is nevertheless a fascinating link between mineral collecting and materials science. A property that first catches the eye as an unusual colour effect can also inspire useful ways of recording light exposure.
Our laboratory evidence
The report retained below identifies the beads of sample 10679 as sodalite-group material, essentially hackmanite, with very iron-poor phlogopite inclusions. It does not record a tenebrescence experiment or supply a locality. That makes the report valuable for composition while leaving the optical behaviour to be documented separately. Another specimen in our library, offered under the hackmanite name, was identified as a sodalite-bearing syenite. The two reports are separate pieces of evidence, not interchangeable descriptions of every item sold under the name.
Care and observation
Sodalite has a Mohs hardness of approximately 5½–6 and is brittle. Protect finished pieces from abrasion by harder gems and from impacts. Use gentle cleaning and avoid chemical dips, abrasives, steam and ultrasonic equipment where mixed minerals or fractures may be present. When exploring the light response, follow the UV lamp manufacturer's instructions and protect eyes from the beam. Record the lamp wavelength, exposure time and lighting used for each photograph. Those details make a colour comparison more useful than a dramatic image alone, and they help preserve the individual story of the specimen.
Sources and further reading
- Handbook of Mineralogy: Sodalite
- University of Turku: Repeatable colour change in Hackmanite
- University of Turku: Intelligent sensing research
View the original test results
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 an area of the specimen.
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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 spectrum of spot 1 in Fig. 2 (sodalite group).
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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 spectrum of spot 1 in Fig. 3 (phlogopite).
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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 map of the area shown in Fig. 2. Sodium: yellow, potassium: purple.
Read the report as text
Analytical Result Report Sample id: 10679 (#9 bracelet) Submitted by: Soul Body Gems Date completed: 8-30-2024 Operating conditions: An AMRAY 1830 SEM operated at 25 kV acceleration potential, 24 mm working distance, 0 degrees sample tilt, coated with 250 Å carbon, and also using the attached XRF unit operated at 30 kV. Fig. 1: Photograph of the specimen. The beads are about 0.6 cm in maximum dimension. Fig.2: Backscattered electron image of an area of the specimen. Fig. 3: Energy dispersive spectrum of spot 1 in Fig. 2 (sodalite group). Fig. 4: Energy dispersive spectrum of spot 1 in Fig. 3 (phlogopite). Fig. 5: X-ray map of the area shown in Fig. 2. Sodium: yellow, potassium: purple. Summary of findings: This specimen (Fig. 1) is not a common material. The beads are made from a sodalite group mineral, essentially what is called hackmanite (Figs. 2,3 and 5). Some inclusions of very iron-poor phlogopite are also present (Figs. 2, 4 and 5). Sodalite group species only occur in silica undersaturated rock types such as nepheline syenite. Date: August 30, 2024 Signature
