Conca dei Marini - Grotta dello Smeraldo
The cave is called "emerald", because the sun light comes in, throught a tunnel under the water (the tunnel connects the cave to the open sea), it makes the emerald colour.
You can reach to the "Grotta dello Smeraldo" by car or bus and also by boat. From La Praia or from Amalfi's harbour many boats go to and for the cave, each hour
I didn't take a pic inside the cave.
This one cames from Cooperativa Sant'Andrea

antipasto di mare
Tibetan goats
Praiano Village
restaurant - alfonso a mare - praiano