DetailsAmygdaloidal Basalt is a variety of lava which has crystal infilled former gas vesicles often appearing as small white spots in the otherwise black finely crystalline basalt. The infill usually occurs as a secondary process. Mineral rich volcanic fluids or ground water deposit minerals such as Quartz, Calcite & sometimes Zeolites in the solidified gas bubbles. These particular samples come from the Isle of Skye. Specimens are supplied in a polythene bag in lots of 1 kg with a label.