Kalamata olives are left to ripen to a deep purple (not black) on the tree, and are cured like other olives (brine or oil). California olives start green, and t

Kalamata olives are left to ripen to a deep purple (not black) on the tree, and are cured like other olives (brine or oil). California olives start green, and the curing process turns them black. See https://www.youtube.com/watch?v=xKWBJkaoRjM https://www.youtube.com/watch?v=xKWBJkaoRjM