I have no idea what this is. House is located in central VT- think cold winters and moist summers.
The area is a crawl space with no vapor barrier below a kitchen. Plumbing drain pipes near by but no sign of leakage. Soil in crawlspace was dry- basement adjoining was wet.
Looks like my kids science project went awry. It was “rock like” but broke apart easy. Yellowish, sporadic.
Didn’t taste like much 
Possibly sulfur…
3 Likes
Interesting?? I tried to google some images or topics on it. I admittedly don’t have the web surfing skills some folks have. Looks like a good place to grow blueberries though if that’s the case.
1 Like
Wow, I’d get the hell out of there and go get tested for radioactive exposure 
No idea what that is.
1 Like
That’s why my urine is glowing now!
I was thinking back to my time on Mauna Kea and Haleakala and don’t recall seeing sulfur like this.
2 Likes
Is it lichen? What did it feel like?
2 Likes
4 Likes
Correct Larry
Okay…really old petrified lichen then. LOL!
2 Likes
Good thought, but lichen does photosynthesize which requires sunlight. This is in a crawlspace with very minimal activity in years, so minimal to almost no light enters. It feels more mineral than biological.
2 Likes
Efflorescence of some yellowish mineral in the soil. Moisture wicked up into the clods and deposited the minerals.
*Efflorescence is normally the white, powdery scum that can *
*appear on masonry walls after construction but can also be *
brown green or yellow, depending on the type of salts.
2 Likes
From the pics it has a fungus-like appearance. You could recommend a mold test to your buyer.
Since no one has asked. The REAL test; What did it taste like?
2 Likes
Here ya go Bob Somewhat lacking, but…