Caring for a stone sink is not nearly as complicated as most people believe. In fact, you probably have all you need in your home already; dishwashing soap and bleach. Tough food stains (including wine & beets) may appear on your sink, but can easily be removed with common bleach, without harming your stone, and that includes white marble! Sealers are not recommended, they can wear off quickly and frankly there not as tough as your stone.
Marble, If you want to maintain the high gloss polished look, try to avoid acidic foods (lemon juice, etc.) from sitting in your marble sink, as these may dull the finish. However over years of use this is typically unavoidable and can be considered part of the natural aging beauty of a stone sink. If on the other hand you prefer that new high polished look, consider hiring a technician (found at a stone countertop company) to re-polish the inside bottom of your sink, as this is usually the only area needed. This can be done fairly quickly with diamond grinding pads and water.
Travertine and Black Lava both have naturally occurring small holes which required filling during the production process, the filling is a mixture of epoxy and ground stone, once cured they are rigorously tested to provide many years of maintenance free service. But just like a cavity toothfilling, at some point it maybecome loose and require re-filling, this can be done with 100% epoxy or with a mixture of ground stone, just be sure the hole is clean and dry, fill, let completely cure (24-48 hours), using a razor blade slice off any excess. Having said that, it is not uncommon for these sinks to be maintenance free for 10 years or more.
Granite,is one of the toughest stones available. Water spots may appear on the surface (from hard mineral water), but can easily be removed with a razor blade.
Limestone, we select only the hardest and best grades, all make excellent choices for sink use. Can easily be cleaned with mild soap, or for tough stains use common bleach.
We do not recommend the use of chemical sealers or enhancers, these are not as tough as your stone and will typically wear off and leave splotchy areas that will then require constant re-sealing.