The moonstone (Sandakada Pahana) is a permanent feature of the buddhist building of all historical periods. This is a semi circular piece of stone which stood at the foot of a flight of steps in most buddhist buildings. Although the moonstone is generally semi circular, Sometimes you can come across square moonstones. It is thought that the moon stones originated as blank square stone and later developed in to a semi circular shape. This again developed to include multitude of carved decorations in later stages. But the moonstones in the monasteries where the forest dwelling monks lived maintained the blank semi circular shape.
The design of the moonstone has undergone many changes over time, But the moonstones show the highest level of creativity towards the end of the Anuradhapura Era.
In most of the moonstones of Anuradhapura Era, the outer edge is designed with a ring of flames and below that is a ring filled with 4 types of animals – The elephant, the horse, the lion, and the bull chasing each other. Some moonstones show these beasts in their own semi circular band. The next is a semi circle of a creeper with a wavy stem with foliage (“liyawela”). Next is a line of swans with a twig of flower and a leaf on their mouth. Next is again a floral pattern and at the centre is lotus with petals all around the semi circle on the moonstone