All wood is a product of nature, and nature provides differences in the soil and weather conditions that affect grain patterns and color. These variations are what create the beauty of real wood: the infinite variation of grain, texture, and color.
It is the nature of hardwoods to have mineral streaks (light brown, dark brown, black, green, red or white to black areas in the wood) and variation in graining.
These variations in color and grain pattern are what make wood cabinets desirable. For wood lovers, these variations are very attractive and are considered a desired effect.
Finished cabinets will be unique, especially when they get a stained finish that emphasizes and exhibits the natural grain of the wood.