AM-2026-00016-A · Corundum, var. sapphirearchived
| designation | Corundum, var. sapphire |
|---|---|
| chemical formula | Al₂O₃ |
| classification | Oxide |
| crystal system | Trigonal |
| mohs hardness | 9 |
| density (g/cm³) | 4.05 |
| colour | Variable; red (ruby), blue (sapphire), grey, brown |
| type locality | Antananarivo region, Madagascar |
reported peaks (cm⁻¹): 378, 419, 612, 645, 751
Waterworn pebble of blue-grey colouration with vitreous lustre on abraded surfaces. Photoluminescence under 405 nm excitation exhibits a long-lived component with decay extending beyond 40 ms, well outside the range reported for Cr³⁺-related emission in this matrix. The extended component reproduces across excitation cycles and is not suppressed by cooling to 80 K. An additional Raman feature at 612 cm⁻¹ is present alongside the baseline set and is not accounted for by the published phonon spectrum of α-Al₂O₃. Cross-facility measurements agree within experimental uncertainty. No mechanism has been advanced.
Events recorded against this accession in the registry's printed custody book. Operator initials are anonymous. Storage codes follow the convention vault-shelf-drawer.
| timestamp | stage | detail | op. |
|---|---|---|---|
| 2026-08-14 09:43 UTC | intake | weighed, dimensioned, photographed; container sealed and labelled with the accession identifier | H.D. |
| 2026-08-19 16:37 UTC | pass A | visual inspection · density (Archimedes) · mass to ±0.01 g | V.O. |
| 2026-09-01 14:55 UTC | pass B | Raman acquisition; 5 peaks above prominence threshold instrument: Renishaw inVia (785 nm) ref. checked: AMCSD #5196 | V.O. |
physical location: vault A · shelf 06 · drawer 09 · last documented inspection: 2026-09-01 14:55 UTC