Azurite mineral
Azurite is the monoclinic copper hydroxycarbonate mineral Cu3(CO3)2(OH)2, distinct from malachite, calcite, generic copper carbonate and elemental copper. The September 2026 IMA list gives grandfathered status G and original-description year 1824. A laboratory bacterial study assigns a minor diffraction feature in a mixed precipitate to azurite; this does not establish a pure azurite product or a phase-specific copper recovery yield. No criticality designation is inherited from copper.
Microbial & Biochemical Mechanisms (1)
Azurite assignment in a bacterial-culture-associated mixed carbonate precipitate
biomineralization
Microbial
Associated Organisms:
Sporosarcina soli (NCBITaxon:334736)
Kang and colleagues assigned azurite, malachite, calcite and copper carbonate in an XRD pattern of precipitate associated with the ureolytic isolate designated Sporosarcina soli B-22. The species mapping follows the paper and its cited sequence, while the B-22 versus B7-22 strain-label discrepancy is unresolved. Ureolysis, increasing pH and carbonate precipitation provide a proposed explanation; the experiment does not demonstrate a unique enzyme pathway or exclude matched chemical precipitation. The accepted azurite observation is qualitative and belongs to a mixed solid.
Experimental Context & Analytical Limits:
Bacteria were isolated from abandoned-mine soil at Imgi, Busan, Korea. Isolation BPU agar contained 3 g/L beef extract, 5 g/L peptone, 20 g/L urea, 10 g/L microagar and 100 micrograms/mL cycloheximide at pH 7, incubated at 30°C for three days. YA broth was 20 g/L yeast extract and 10 g/L ammonium sulfate, pH 7. The calcite-production protocol describes 24 h in YA followed by 72 h in BPU at 30°C and 200 rpm, then mixing 500 microlitres of bacterial suspension with 500 microlitres of 350 mM calcium chloride dihydrate solution. Figure 7 identifies its XRD material as B-22 grown in BPU, but the exact copper dose and correspondence to this generic calcite protocol are not fully specified. The microscopy/diffraction preparation placed suspension on glass and dried it at 50°C; SEM samples were water-resuspended, redried and platinum-coated. The separate YA copper-removal assay used synthetic copper salts, not a real mine-waste feed. This is a laboratory culture and processed-solid observation, not industrial mineral recovery.
Bacteria were isolated from abandoned-mine soil at Imgi, Busan, Korea. Isolation BPU agar contained 3 g/L beef extract, 5 g/L peptone, 20 g/L urea, 10 g/L microagar and 100 micrograms/mL cycloheximide at pH 7, incubated at 30°C for three days. YA broth was 20 g/L yeast extract and 10 g/L ammonium sulfate, pH 7. The calcite-production protocol describes 24 h in YA followed by 72 h in BPU at 30°C and 200 rpm, then mixing 500 microlitres of bacterial suspension with 500 microlitres of 350 mM calcium chloride dihydrate solution. Figure 7 identifies its XRD material as B-22 grown in BPU, but the exact copper dose and correspondence to this generic calcite protocol are not fully specified. The microscopy/diffraction preparation placed suspension on glass and dried it at 50°C; SEM samples were water-resuspended, redried and platinum-coated. The separate YA copper-removal assay used synthetic copper salts, not a real mine-waste feed. This is a laboratory culture and processed-solid observation, not industrial mineral recovery.
Curated Evidence Points:
Support
Source:
kang2016
Page 210 Figure 7 labels a small feature A as azurite alongside M (malachite), C (calcite) and U (copper carbonate). The SEM and XRD Results explicitly assign these phases. Figure 6 supplies morphology of calcium- and copper-carbonate-associated solids but cannot identify azurite by shape alone. No raw diffraction data, phase-fit uncertainty, quantitative azurite fraction or separately isolated azurite product is provided. The source’s abbreviated formula in prose omits a hydroxyl subscript; this record uses the authority formula and does not interpret that printing inconsistency as evidence for a different species.
Partial
Source:
kang2016
Methods p. 208 describe a separate YA assay with 5 microlitres of 12-hour culture added to 45 mL broth in a 100 mL flask, nominally 5 mM urea, 25 mM CaCl2 and 2 mM copper, at 30°C and 200 rpm for 48 h. Controls without added cells are stated for all experiments. Solution removal is calculated from initial and final supernatant ICP-OES concentrations after centrifugation, not from recovered mineral mass. Figure 8 and p. 211 instead describe 72 h and report 61.8% copper removal; the p. 211 dose is printed as 2 M, while the figure’s starting Cu concentration is about 270 mg/L, inconsistent with nominal 2 mM elemental Cu. These values are retained as source inconsistencies, not reconciled or assigned to azurite. Figure 7 uses BPU whereas Figure 8 and the removal protocol use YA.
Partial
Source:
kang2016
Figures 1–3 support the authors’ isolate assignment, urease activity and copper tolerance; Figure 8 shows increasing pH in the B-22 culture. However, an azurite-specific uninoculated diffraction comparison, matched-pH chemical control, urease-inhibited treatment and phase-resolved copper mass balance are not shown. The generic statement that controls were included is not equivalent to a reported azurite-specific control result. The distinct sand-column and EPS experiments in Figures 4–5 do not establish an azurite-specific contribution to immobilization.
Partial
Source:
genbank_kj485701
The accession cited for B-22 resolves to Sporosarcina soli B7-22 and NCBI taxon 334736, with soil as isolation source. This supports the species label but does not independently authenticate the differently labelled experimental isolate. A submission address is not treated as specimen geography. The paper reports 99% 16S similarity; species-level mapping does not remove the unresolved strain-label mismatch.
Sources & References
-
ima_202609: IMA-CNMNC master list, September 2026, definitions pp. 1–2 and Azurite row p. 18: Cu3(CO3)2(OH)2, G, 1824.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15) -
handbook_azurite: Handbook of Mineralogy. Azurite. Version 1, 2001–2005, one-page entry; formula, monoclinic structure and powder pattern.
https://www.handbookofmineralogy.org/pdfs/azurite.pdf (accessed 2026-10-15) -
kang2016: Kang, Shin, Anbu, Nam and So (2016). Biosequestration of copper by bacteria isolated from an abandoned mine by using microbially induced calcite precipitation. Journal of General and Applied Microbiology 62:206–212. Complete seven-page original, Methods pp. 207–208 and Figures 1–8, especially mixed-phase Figure 7 and distinct solution assay Figure 8.
https://doi.org/10.2323/jgam.2016.03.001 (accessed 2026-10-15) -
genbank_kj485701: GenBank KJ485701.1. Sporosarcina soli strain B7-22 partial 16S rRNA sequence, 1481 bp; source taxon 334736. The accession strain label differs from the paper’s B-22 label.
https://www.ncbi.nlm.nih.gov/nuccore/KJ485701.1 (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T01:20:49.712795+00:00 |
codex (GPT-6; codex) | CREATE | Created azurite mineral record for a source-assigned minor phase in a mixed bacterial carbonate precipitate, preserving strain-label and assay-condition conflicts and excluding phase-specific recovery. |
Record source: data/records/azurite.yaml