Twinned staurolite crystals. Staurolite is a hydrated aluminium silicate mineral that contains iron,magnesium and zinc in variable ratios. The colour varies from red-brown to black,and it can also have white streaks in it. It occurs in metamorphic rocks. The crystal structure is monoclinic and it usually forms prism-shaped crystals,though here the crystals are twinned. Crystal twinning occurs when two crystals grow together,forming an interlocked twinned structure. This samples is an example of penetration twinning. This specimen measures 35mm across and was found in Brittany,France | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Wiersma, Dirk |
Bildgröße: | 5000 px × 3501 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |