Natural Crystals

I have been in to crystals for well over 10/11 years, I have quite a collection of natural crystals. I was wondering if anyone on here would be interested in knowing the truth behind some crystals which us crystal uses are sold, that are:

1, Not handleable, what I mean by this is, there are some which must be kept dry at all times, so moisture from your own hands can damage it. Covered in tiny crystals, a flaky, crumbly/powdery surface must be handled very carefully. In truth I never handle them, they live in a cabinet.

2, Heat-treated, acid washed/acid enhanced, or dyed or coated to change its appearance to be sold under a different name.

3, Miss sold crystals or information. (This will be based on my own experience)

4, Fake.

Hopefully it will help anyone who is either wanting or getting into crystals and would like to know from someone who is quite experienced what to look out for and how to handle natural crystals because you cannot treat them the same way as tumbled.