Diamonds come out of earthly processes as I understand it....volcanic pipes....
I know it takes a lot of pressure and heat applied over a long period of time.. just a thought.
You are right about diamonds and the volcanic pipes. There has recently been a major diamond find around VPs in Canada north of Yellowknife.
The major crater in Siberia might be Popigai (60 miles in diameter). It and the Chesapeake Crater (50 miles in diameter), running from Norfolk to Exmore on the Delmarva Peninsula, as well as a 9 mile diameter crater off Toms River, NJ, all were formed about 35 million years ago. The age is about the same and they all struck from the same direction and at the same low angle, so it might have been an event like the recent Jupiter extraveganza.
I also suspect that further study may show that the massive Siberian Traps, formed 250 million years ago at the end Permian catastrophic extinction time, could have been formed by a very large boloid and then buried in magma.
Many craters are the source of a varied array of minerals and metals, including oil. The 180 mi. diameter Vredefort crater in South Africa is a major source of gold and uranium. The Sudbury in Ontario, Canada (50 mi. diameter) has many important metals. Some of the oil in Oklahoma and the North Sea has a crater origin. We need to explore more craters and find more craters (and oil, I hope, I hope).