White crystalline compound found in crawlspace

I completed an inspection this last week and found a compound that I have never seen before. At first it looked like straight strands of fiberglass. It is the same diameter as fiberglass found in insulation but it is anywhere in length from 1/32 to 1/2 inch in length. There was a piece of plastic laying on the dirt and this compound was all around the edge of the plastic. Under the middle of the plastic it was damp and the rest of the dirt was very dry. It looks to be some sort of crytalline formation but it is very fragile. Any one have a suggestion or where to turn for help.:neutral:

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I used to see this in crawlspaces of a building development in Hercules, California that was built in the early 80’s. I never found out exactly what it was but when the homes had poor drainage the amount of crystalline was more prodominate. I attribute to something like the concrete efflorescence.



You guys got it right. We had it tested and it turned out to be mineral salt. It was found around the edge of some plastic where the moisture would meet the air and evaporate. It is the same as concrete efforescence. I had never seen it form on dirt before, especially from this very dry dirt.