AM-2020-10001-A · Chalcedonyarchived
physical & structuralrev. 4
| designation | Chalcedony |
|---|---|
| chemical formula | SiO₂ |
| classification | Tectosilicate / cryptocrystalline quartz |
| crystal system | Trigonal |
| mohs hardness | 6.5 – 7 |
| density (g/cm³) | 2.64 |
| colour | Faintly banded grey |
| type locality | Ouro Preto, Minas Gerais, Brazil |
raman spectroscopy532 nm · pass A
reported peaks (cm⁻¹): 130, 465, 501
notessubmitter remarks + registry
Photographic record retained. Specimen temperature held at lab ambient throughout intake.
chain of custody6 events · 4 seal-breaks
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. |
|---|---|---|---|
| 2020-09-12 13:10 UTC | intake | weighed, dimensioned, photographed; container sealed and labelled with the accession identifier | H.D. |
| 2020-09-13 09:20 UTC | pass A | visual inspection · density (Archimedes) · mass to ±0.01 g | C.B. |
| 2020-09-18 12:25 UTC | pass B | Raman acquisition; 3 peaks above prominence threshold instrument: Horiba LabRAM HR (532 nm) ref. checked: AMCSD #1657 | C.B. |
| 2020-09-20 16:56 UTC | storage | re-bagged, label re-printed; placed in vault D, shelf 20, drawer 05 | H.D. |
| 2022-09-20 14:33 UTC | re-inspection | seal intact · label legible · no visible degradation | N.P. |
| 2024-09-19 16:27 UTC | re-inspection | seal intact · label legible · no visible degradation | N.P. |
physical location: vault D · shelf 20 · drawer 05 · last documented inspection: 2024-09-19 16:27 UTC