The rest of all “stains” are really etches and these are relegated to marble and stones that are really marble, but sometimes sold as quartzite (ie: Super White, Brown Fantasy and other stones that sell really well when you tell the customer it is a quartzite when in fact it is an etch- able marble!). Etches are not stains, but are in fact damaged areas due to a chemical reaction between the calcium in the stone and the acidic liquid that has physically converted the stone. This is not a stain and not going to come out or be repaired easily or inexpensively. Light etching can sometimes be removed by hand with commercially available etch removal kits while deep etches required special equipment, lots of water and highly skilled and experienced stone personal to physically remove enough stone to remove the etched surface.
In case you still have questions, want a more technical break down of sealer, or want to help us become Youtube sensations! Watch the "What is Sealer for Granite, Marble, Quartzite, and Travertine Countertops?" video on Youtube. Its already received over 70,500 views and has been featured and share on numerous industry websites, blogs, and articles. Guess we know what we're talking about!