Picture posting is enabled for all :)
I want to get a few bags of gypsum to break down the heavy clay soil I'll be adding lots of organic matter too, of course.
I am not keen to get it from a builders' merchant as their gypsum may have other stuff in it that could be harmful for gardening purposes. I'm looking for an outlet that supplies it specifically for gardening.
you are correct in saying that the finished product in the builders merchants does have additived and is not pure gypsum.