The Grotta dello Smeraldo (Italian for "Emerald Cave ") is a sea cave located in Conca dei Marini, Italy, on the Amalfi
It is one of several sea caves, worldwide, that is flooded with a brilliant blue or emerald light. The quality and nature of the color in each cave is determined by the unique lighting conditions in that particular cave. The cave, which is located along the Amalfi Coast, is partly filled with water. The surface area of the water measures roughly 45 x 32 meters, with a cavern roof about 24 meters above water level.
Unlike the more famous Blue Cave a few miles to the west on Capri
, the Grotta dello Smeraldo has no natural outlet above the waterline. The only opening to the outside world is just below the water level. Refracted sunlight entering the cavern through the opening gives the water its characteristic emerald glow during daylight hours.
The absence of a natural opening above the waterline meant that the grotto’s existence remained unknown for many years. It was discovered by a fisherman named Luigi Buoncore in 1932.
The cave is accessible from Strada Statale 163, the main road along the Amalfi Coast. There is a small parking lot beside an elevator which takes visitors down to cave level, where they board boats that take them through the grotto.