Citrine and sapphire gemstones. Fine and poor examples of gem cutting and polishing. At left is a superbly cut citrine (a yellow variety of quartz),while at right is a poorly cut sapphire (blue),a variety of the mineral corundum (aluminium oxide) | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Natural History Museum, London |
Bildgröße: | 4747 px × 3682 px |
Modell-Rechte: | nicht erforderlich |
Restrictions: | - |