Which material is suitable for interior window sills?

We have the following materials to choose from for interior window sills:

-Granite
-Marble
-Artificial stone Helopal

In terms of appearance, we only like Marble and Helopal for the interior.

What are the respective advantages/disadvantages? What would you recommend?

It is actually just a matter of taste and price. Marble is somewhat more delicate.

Marble is sensitive to acid. Important to know for the kitchen :)

We have dark marble with a rough sandblasted non-recessed surface. It is totally great and insensitive. And you don’t see the dust immediately :-)