The qualities of onyx are comparable to those of marble. Softer and less durable than granite, it requires occasional maintenance, but that's a small price to pay for the majestic ambiance of these tiles. The movement and color variation are unsurpassed in other stone varieties. Onyx is prone to etching and staining from acids such as ketchup, lemons, alcohol and household cleaners. Onyx is a softer stone best placed where it won't be used or abused on a day-to-day basis. It's porous and needs to be sealed, otherwise, it will absorb water and liquids easily which tend to stain the stone. Once a stain is absorbed into onyx, it is extremely hard to remove. Onyx can be finished with a polished surface.