Taj Mahal quartzite is a natural stone, so yes, it needs to be sealed.

I know this is late. When we had ours installed they said it didn't need a sealant. We did, it was something special they had to use but I don't remember the details. We have done nothing to redo - whatever it was and it has been several years. It just keeps looking better. My friend had the same counter top placed a few months after mine was installed and did not seal, has held up beautifully and looks no different than mine today. It does not absorb anything. It does not destroy. I love it even more than when it was first installed.