Grains Found in Georgia Traced to Huge Asteroid Impact ATLANTA (AP) -- A layer of quartz grains found in an east Georgia kaolin mine have been traced to the impact of a giant asteroid that crashed near the mouth of the Chesapeake Bay 35 million years ago.    The 54-mile-wide crater left by the meteor, the sixth-largest in the world, has previously been identified as the source of a rare mineral called Georgiaite...