Granite countertops are made from low-grade, mid-grade and high-grade granite. Low-grade granite countertops come in common colors and often require plywood backing for strength. Mid-grade granite countertops have average patterns and may contain some pitting. High-grade granite has uncommon colors, veins and patterns, and it contains more minerals.
Grades of granite are determined by each individual wholesaler. Granite slab grading is determined by thickness, colors, veins, marking and pitting, country of origin and the amount of soft minerals embedded within it. Granite comes in many colors, with beige and green most readily available, while blue, purple and red are least common.