Table 2 Varimax-rotated principal component (VPCA) results for different wavelength ranges of sherd (S) and powder (P) samples.
From: Reflectance spectroscopy reveals mineralogy and preservation of ceramics from the Bidong Shipwreck
Spectral range | Sample type | Number of PCs | PC | Mineral identification (USGS) |
|---|---|---|---|---|
Visible (VIS) (400–700 nm) | S | 3 | 1 | Illite |
2 | Diopside (pyroxene) | |||
3 | Chrysocolla | |||
P | 2 | 1 | Pyroxene | |
2 | Chalcopyrite | |||
Near-infrared NIR (700–2500 nm) | S | 7 | 1 | Hematite |
2 | Ferrihydrite | |||
3 | Sodium bicarbonate | |||
4 | Lazurite | |||
5 | Sphalerite | |||
6 | Illite | |||
7 | Ammonio-Smectite | |||
P | 4 | 1 | Hematite | |
2 | Gaylussite | |||
3 | Sodium bicarbonate | |||
4 | Illite | |||
Full range (VIS + NIR) (350–2500 nm) | S | 8 | 1 | Hematite |
2 | Ferrihydrite | |||
3 | Sodium bicarbonate | |||
4 | Hedenbergite (pyroxene | |||
5 | Sphalerite | |||
6 | Laumontite-Zeolite | |||
7 | Illite | |||
8 | Chlorite | |||
P | 5 | 1 | Hematite | |
2 | Hedenbergite (pyroxene) | |||
3 | Sodium bicarbonate | |||
4 | Sphalerite | |||
5 | Illite |
