Chondrus crispus, commonly called Irish moss or carrageenan moss, is a species of red seaweed that grows along the rocky shores of the Atlantic coast of Europe and North America. It is soft and cartilaginous, and ranges in color from greenish-yellow to red, dark purple to purplish-brown.
The main component is a mucilaginous body, consisting of the polysaccharide carrageenan, which makes up 55% of its dry weight. The body also consists of almost 10% protein by dry weight and approximately 15% mineral matter by dry weight.
