Deformed Quartz
Geologist Dr. Doyle Watts of Wright State University at Dayton investigated the impact crater region extensively in the 1970s. His team drilled down to 1,700 feet and collected samples of rock from the depths. They discovered deformed quartz. This is quartz, but it has been slightly melted by a huge explosion force. Watts stated that petroleum companies ran sound waves down to 10,000 feet, and still found ground deformation at those depths. The conclusion reached is the impact happened about 256 million years in the past, and the force caused an explosion greater than an atomic bomb.
Iridium
Watts and his colleagues also found huge deposits of iridium in the region. This is a metal crystal, and the amount found at a thousand feet deep was 10 times greater than what is normally found in any region of the earth. Iridium is usually found in asteroids or comets. The conclusion was that the meteorite or comet was iridium-rich.
Calcite
Calcite is a white mineral, crystalline in structure. it was found in the Brush creek area. According to OpticalMineralogy.com, it is a very common mineral in the earth. It is one of the chief components of marble rock and limestone. Calcite is actually crushed seashells from millions of years ago.
Hexahydrite
Hexahydrite is actually a crystalline mineral salt, and is water-soluble. At one time in the 1930s it was thought to be a rare mineral, but deposits of it were found in various counties in Ohio, including the Brush Creek area. It is not a new discovery, having been written about in the Ohio Journal of Science in 1963. According to Geologists Wilfrid Foster and Karl Hoover, it bears a strong resemblance to Epsomite, which the common "Epsom Salt" is made out of.