To Seal or Enhance
When you are spending the extra money on a natural stone floors or walls you will want to preserve and protect your investment. A sealer or stone enhancer will give you extra protection in high traffic or high use areas. The choice between the two is one based on personal preference, but it can leave you with a different look in the end.
No matter what the product or material you plan to use it on, always test on an extra piece or cut off. With most sealers you should be left with minimal change in your stone and grout once the sealer has soaked in, just remember to wipe away any excess and take special care with any polished material to make sure to buff out any haze. If you have a slate or a marble that can benefit from an enhancer be sure to test with multiple coats on a sample piece. Enhancers typically leave your stone and grout slightly darker and can bring character out of your stone.
Be sure to follow any instructions provided by the manufacturer and take care when shopping for products, since some leave matte or polished finishes. As always if you do not feel comfortable, hire a professional before you are in over your head.