Raphids are needle like long slender calcium oxalate crystals usually lying parallel to each other in a bundle, which is some times found in a special sac-like cell. Raphids are commonly found in Alocasia, Colocasia, Pistia etc. The crystals of calcium carbonate are commonly known as cystoliths usually they occur in epidermal cells of leaves of many flowering plants (plants of family Moraceae, Urticaceae, Acanthaceae, Cucurbitaceae etc.)