In its fresh condition it is soft and cartilaginous, varying in color from a greenish-yellow, through red, to a dark purple or purplish-brown.

The principal constituent is a mucilaginous body, made of the polysaccharide carrageenan, which constitutes 55% of its dry weight.

The branches are 2–15 mm broad and firm in texture, and the color ranges from bright green towards the surface of the water, to deep red at greater depths.

Mastocarpus stellatus (Stackhouse) Guiry is a similar species which can be readily distinguished by its strongly channelled and often somewhat twisted thalli.

The three stages (male, female, and sporophyte) are difficult to distinguish when they are not fertile; however, the gametophytes often show a blue iridescence.

Chondrus crispus is commonly found along the shores of Ireland and the coast of Europe including Iceland, the Faroe Islands,[4] western Baltic Sea to southern Spain.

[9][10] C. crispus is an industrial source of carrageenan commonly used as a thickener and stabilizer in milk products, such as ice cream and processed foods.