Granite grading can be confusing because there is no standard, international grading system for granite. Rather, granite grades and prices are set by manufacturers to reflect the supply and demand of colours and cuts of slabs, not the quality and strength of the stone. The good news: that means low-grade slabs can make countertops that are equally durable and beautiful as their high-grade counterparts, but at a fraction of the price.
The second-choice or second-quality grade generally refers to stones that have natural discolouration or a high concentration of veins and quartz pockets that require the slabs to be cut into smaller pieces that might not work for many countertops. But if you find a piece that fits, it can be a good deal because the strength is the same as higher grades. These are the lowest priced grades of granite.
Commercial grade granite can often be the best deal for countertops. The designation generally means the slab does not possess the same clarity and depth of colour as other grades. The term might also mean the polish on the surface of the granite is not as fine as what you will find on higher grades. Sometimes it might also mean there are softer minerals or more veins in these slabs than in higher grade stones, which would be the only reason to think twice about using a commercial grade slab for a countertop. But often highly desirable or rare granites that have higher grades are full of veins, meaning countertops made from commercial grade stones can be more durable even though they cost significantly less.
First Choice and Higher Grades
No matter what grading system your seller uses, you will probably encounter granite labelled "first choice" or "AA" quality or "exotic" grade, referring to the most expensive slabs. These designations are frequently granted to granite with rare colours or distinctive patterns that make it more valuable, but not necessarily more durable than lower grades. Because granite is a natural material, even the most desirable grades contain veins, fissures and other imperfections, meaning the slab would have to be cut in ways that could make it difficult to use for many countertops.