What is more expensive diamond or padparadscha?

Padparadscha is a pink-orange corundum; diamond is the hardest mineral on earth.

Prices for Padparadscha can be similar to what you'd pay for a fine ruby or emerald.

In order to compare, one would present the specifics of equal gemstones: equal in carat weight, clarity, colour and Excellence of cut. In this case, most of the time, the diamond would be more expensive.