Grade Granite Slabs
The standard grades of granite countertops from the quarries are Select, Semi Select, Standard, Commercial. These may vary from different countries but from the largest countries that stone are imported from these terms are used to define the grades of material.
Commercial slabs are of the lowest quality. They will have pits and fishers as well as other imperfections that disqualify them from being considers standard quality. These materials are typically used for floors and other large scale applications where the waste factor can be higher which is ofset by the reduced cost of the material. It is not recommended to have commercial grade material in you home due to these imperfections and lower quality.
Standard quality slabs maintain the look and feel as well as hold the definition standard that the quarry sets for the specific material color as they define it. Basically the quarry that sells the blocks of material set the standard for the color before it it sold and shipped to the US. Standard Quality Slabs are perfect for home kitchen and bathroom use. These slabs have minor imperfections as defined by select materials.
Select and Semi Select are near perfect stones and are the definition of the perfect stone to represent the color definition. These slabs are the “gold standard” and are typically very expensive. From one block of material it is rare to have 1 entire slab defined as Semi select or Select.
Hope this helps you to understand how materials are graded for quality and intended use.