After putting this evaporated goo in my food dehydrator at 165F, it resulted in what appeared to be some similar brown looking goo on my plate. I was disappointed until I started chinking away at it with a razor blade, where I discovered that it was crystalline.
However, it is so sticky, and rather hard. I have lost a lot of material going at it with the razor blade. In fact a piece actually landed in my eye which freaked me out. I washed it out for like 3 minutes and returned back and started using eye protection. (Edit: it's been about 3 hours since this incident. My eye feels fine. I hope it stays that way; edit: It's now been over 12 hours and I am fine.)
I took it out of my food dehydrator and let it cool down for about an hour before I started scraping it. Was this a mistake? Perhaps it would have been easier if I started scraping it immediately after taking it out of the food dehydrator.
So far, I have yielded about 1.1g of brown crystals, whereas I started with about 39g of dried cactus material. So this is a yield of 2.8%. And this doesn't include all the loss I've had just scraping it with my razor blade. I see brown crystals on the floor and the counter and my shirt. But 2.8% is too good to be true right? I assume that implies my brown crystals are not as pure as could be.
I also used a regular ceramic plate instead of a glass evap dish. I now have scratch marks all over that plate. I hope it doesn't mean that my 1.1g of brown crystals contains some plate material! Although, that might explain the higher than expected yield

. None of the glass dishes I saw at Walmart were thin enough to fit inside of my food dehydrator. Next time I'll go buy something better online for this.
Edit: I ended up adding some boiling water to this plate to dissolve the crystals I couldn't get out and then put it back in the dehydrator. After it evaporated I took it out and immediately started scraping. This seemed to be easier compared to scraping after it had cooled down. But it wasn't that much easier. I think these brown crystals that originate from the goo just have a tendency to become pretty hard and sticky, and difficult to work with.