[Krystyna]

https://www.gia.edu/gems-gemology/summer...escription

[Krystyna]

   
Pegmatite Nepheline 
Pegmatitic igneous rock from Tredalen near Larvik. Gray is nepheline, yellowish brown is wöhlerite, black is hornblende, pink is K-feldspar, and gray is magnetite. The width of the specimen 14 cm. From Sand Atlas.
Pegmatytowa Skała Magmowa z Tredalen koło Larviku. 
Szary kolor to Nefelin, żółtawobrązowy to Wöhleryt, czarny to Hornblenda, różowy to Skaleń Potasowy, a szary to Magnetyt. 
Szerokość okazu 14 cm. Z Atlasu Piaskowego 
https://www.alexstrekeisen.it/english/pl...matite.php

[Krystyna]

   
Cancrinite Pegmatite: Yellow Cancrinite with black Biotite, Nepheline and Alkali Feldspar. Litchfield, Maine. 
Photo by W. Cordua, From Wisconsin Geological and Natural History Survey.
Pegmatite Cancrinite 
https://www.alexstrekeisen.it/english/pl...matite.php