The piece I have that is on slate was still leeching tannins, but that is the only one I know of that is. I can't guarantee either way, sorry! Hope you find what you need
The thing is, now that I look back at the pictures even, it is like, "DUH!!! It has an ovipositor" Being told is was male, I never paid attention before!
We live about 3 blocks from two lakes connected by a canal. It is a really beautiful area. I spend a lot of time rooting around in the cold water for just a few pieces, lol, but it is fun in a way. I try to make sure to collect root wood only, as it holds up better in the water. The lake is ringed with ancient tree stumps, but it is rare to find any that has separated.