Prase is a vague term that has been used to describe various types of so-called 'leek green' Quartz - including Quartzite, Quartz and Jasper. The original definition of Prase, dating back to 1912, is Quartz crystals coloured by inclusions of green Actinolite. Fine Prase crystals have been found in Serifos, Greece, and are highly desirable. Prase differs from Prasiolite as it is coloured by mineral inclusions, rather than by the presence of iron within the crystal lattice.