What Are Raphide Crystals?

Raphide crystals are acicular crystals that occur in bundles in the cells of many types of plants. They are usually made of calcium oxalate.

Raphide crystals are needle-shaped crystals. If they are not made of calcium oxalate, they contain calcium carbonate. They are found in more than 200 plant families. The size and appearance of raphides differ within family, genus, and species

Both ends of these crystals are needle-like, but raphides are usually blunt at one end while the other end is sharp. Many plants accumulate raphide crystals as a response to excess calcium.

The word "raphide" is derived from the Greek word "rhaphides," which is the the plural of the word "rhaphis," meaning "needle." The word came into use around 1835.