At least that's what I've always called it. The hard deposits you occasionally find in a set of castors. I'm used to finding a stone or two, but I believe I've set a personal record. Just a touch shy of a quarter pound out of the one beaver.

I've always busted it up to use for lure. Always felt it smelt stronger than regular castor, but that may all be in my head. What do you folks do with it?

Never I have ever found them. I have skun a lot of beaver over the years.

Ive caught my fair share of beaver and have never got barkstone castor. Maybe it's just my area I don't know.

Usually have 2 or 3 annually.

I think I have about 4 or 5 sets in the freezer now.

I got one long ago. The thing was so old it defected on land.

My understanding is
Age
Diet
Activity level

So I guess it’s just a guess..

I agree with Vinke to a degree.

I suspect it is a combo of age, diet and endocrine health of the animal. Probably somewhat like a human who develops a chronic issue of kidney stones.

Had a old acquaintance years ago that was spending once a month in the ER for kidney stone problems.

That's interesting. I found three castors today, out of about 10, with varying amounts of barkstone. These were from two different ponds. I usually find a set or two every year. Im guessing that you, Vinke, and Turtledale have all killed a bunch more beaver than I have.

It is something in the water up there. Look what it does to the women in that region.