Prasiolite 10mmPrasiolite is considered very rare because of how it forms in naturethe conditions required are extremely specific and uncommon. The rarest prasiolite originates from Poland. It begins as amethyst or smoky quartz and can only turn green naturally when exposed to a precise temperature range. If the heat is too low, the stone remains purple; if it is too high, it turns yellow or brown. When nature happens to reach that perfect green window, it is