Onyx is a calcareous stone and has similarities to marble. Therefore, it is prone to etching from acids like ketchup, soy sauce, lemons, and household cleaners. It is also a soft stone and can scratch easily. Do not confuse marble onyx to gem stone quality onyx. The two are very different in hardness.
Pictured is an onyx bathroom counter that had acquired damage during construction. The top had a 20″ long scratch. Factory spiderweb scratches were also evident.
Advanced Stone Restoration resurfaced the damage area as well as the entire counter. The deep scratch and factory scratches were removed. The counters were polished to a high shine – better than the day it left the factory.