These separations are known as "Fissures". They are separations in the stone that occur naturally. This is seen in all granite to a degree, so it is seen in different degrees, depending on the specific stone that you are viewing. Luckily, this is not a flaw but a naturally occurring trait. We will not replace countertops due to fissures.
As far as the pitting goes, it is a common characteristic of natural stone. Since Granite is composed of many different minerals with different degrees of hardness, pits will occur. The pitting does not cause the granite to be less durable, so it does not qualify a slab for replacement.