Larimar Infinity Ring, Size 9

Soft and light-sensitive. Keep out of long direct sun and heat, which can fade the blue. Avoid salt water, long soaks, harsh chemicals and ultrasonic cleaners. Store apart from harder stones.

Larimar comes from one small mountainous area in Barahona province in the southwest Dominican Republic. A parish priest, Miguel Domingo Fuertes Loren, asked permission to mine a blue rock there in 1916, but nothing came of it. In 1974 Miguel Mendez and Peace Corps volunteer Norman Rilling found blue pebbles on a beach at the mouth of the Bahoruco River and followed them upstream to the source at Los Chupaderos, where it is still mined by hand.

Larimar is the blue variety of pectolite, a sodium calcium silicate hydroxide with the formula NaCa2Si3O8(OH). It crystallizes in the triclinic system as tightly packed, radiating fibers. Copper taking the place of some calcium gives the blue. It ranks 4.5 to 5 on the Mohs scale and its color can fade with long exposure to strong light and heat.

• People on the Barahona coast of the Dominican Republic found blue pebbles washed onto the beach and believed the sea itself made them, calling the find Blue Stone until it was traced up the Bahoruco River to the hills.
• Larimar is nicknamed the Atlantis Stone because followers of the American psychic Edgar Cayce linked it to a blue stone he said would be found in the Caribbean, on islands some believed were remnants of Atlantis.
• The name is a modern piece of lore: in 1974 Miguel Mendez joined his daughter's name, Larissa, to mar, the Spanish word for sea.