[Krystyna]

   
Basalt Porphyrite, Plagioclase Porphyrite or Diabase? 
Probably All of them, it is mostly a matter of preference and depends on local traditions. 
White Fhenocrysts are plagioclase crystals. 
The Isle of Mull, Scotland. 
The rock is 8 cm in length.
https://www.sandatlas.org/porphyry/