I am new to this, so, we shall see how I do, I haven't even been on a blog site before, but in my humble opinion the appraiser might be the world or anyone around you.

I think maybe the dream says that these people or whoever 'they' may be can not possibly tell the difference between what your self worth, and what 'they' think your self-worth is. The crumbling of the outside, and the fact that it was clearly not worth as much as your own diamond shows that the worlds view of you is only how they percieve you to be, not how you are. (The diamond representing the inner you in that case)

The tie to the grandmother, and the actual material diamond well, I think its a wee message saying, you will always have the diamond. No matter what anyone else thinks or says, it cannot be appraised, or taken.

yeah, might be quite far past this dream, but I love looking back on mine. Lasting impressions are for reasons me thinks.