All stone is porous to some extent. Granite and Slate are both very low porous and stain-resistant, making stains less of a concern than with other stones. In general, with any spill, a quick clean up is a good idea. Some materials will be more forgiving than others. For example, a puddle of water left on the counter for 30 minutes for some colors (especially lighter), may show a dark spot when the water is wiped away. This spot will then dry up and no evidence will show.
Quartz and Marble are both slightly porous materials and can be subject to stains if abused. In many cases, stains can be prevented by wiping the spill. Marble can be sensitive to oil and acidic based products such as juice, tomatoes, and oils. Travertine is very sensitive to acids and a slight spill of juice can stain the surface. Limestone and Sandstone are both porous and will stain easily.
Stone sealers were introduced to the market in the mid 1990s. Having your stone properly sealed by a professional will increase the stain resistance of the stone. For example, if your stone is 90% stain resistant with no sealer, you may increase the resistance to 95%.
Should you get a stain on your stone, depending on the stone, you may be able to apply a special paste called a poultice, made of liquid cleaner mixed with an absorbent material, to pull the stain out. Check out our experiment to test how granite would hold up to olive oil stains. For information on how to apply a poultice on your countertops click on this link.