I was asked about the stones on my table.
This is a perfectly reasonable question. The answer is that they are not ordinary rocks.
Although not monetarily valuable, these stones occur ONLY in the small area around my home, an area of about 10 to 15 square kilometers.
They are the ejecta (stuff thrown out) of a meteor crater that was formed many millions of years ago. An examination of geological maps and other resources indicate that the crater is long gone, a victim of a combination of erosion and mountain building. These stones remain and are now eroding out of the ancient rocks of the area.
They have become a part of the surface gravels and I collect them for their interest and unusual crystalline structure.
LECTURE ON LARGE METEOR IMPACT THERMONUCLEAR EVENTS COMING!
Some of you may remember the recent meteor air burst near a Russian city. The detonation of that meteor had a yield of about 10 Megaatonnes. Just about the same as many Thermonuclear warheads. I mention this as background to the explanation that follows.
Most folks think meteor = falling rock > Thud! (maybe BIG Thud!). In some cases this is true. Unfortunately, there are exceptions for several reasons. Those can lead to the incident mentioned above, or a Tunguska type of event.
It can happen on a smaller scale too. That is what happened in my area, millions of years ago. Basically, under the wrong conditions, the meteor can trigger a thermonuclear detonation.
If you see a falling meteor at night, you are not seeing the meteor itself. You are seeing a layer of plasma that is HOTTER than any part of the sun. A plasma is simply a gas heated by any means until it is so hot that the electrons are completely removed from the nuclei of the atoms. Some of those atoms in our atmosphere are hydrogen.
If the meteor is large enough or the atmosphere has enough hydrogen sources like moisture or methane, the plasma has most of what is needed to go boom. All else that it needs is to compress the hydrogen nuclei together. This requires a fair sized meteor or the meteor hitting something that does not yield.
The incoming meteor is the hammer and the ground is the anvil. The plasma gets squashed between them and the hydrogen fuses over to helium. Most of you know that process. It is what makes a hydrogen bomb work. The meteor driven process is not efficient, but it is adequate.
How does all of this relate to my little stones?
The ancient meteor hit a formation of red granite or rhyolite. Under the unique conditions of heat and pressure involved, atoms of the earthly stone and some of the siliceous material of the meteor combined into a new mineral that is found no other place on Earth.
That is the history of these little stones and why I find them fascinating.
And for those who ask, THEY ARE NOT RADIOACTIVE!