Crinoidal Limestone Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. Crinoids are an ancient fossil group that first appeared in the seas in the middle Cambrian period about 500 million years ago. Crinoids are sea animals that had long stems, cup-like bodies, and long filter arms, that look so much like flowers that they are called "Sea lilies". Crinoidal Limestone reduces tiredness and fatigue and to help with detoxing and digestive disorders. They also help with rheumatism. Fossils may help to relieve anxiety and stress, balance the emotions and increase our levels of self-confidence. They are also said to promote a sense of pride and success in business. Crinoidal Limestone helps to enhance our telepathic abilities and stimulate the mind.