Possible shell mount?

[knsrn]

Ok, first attempt at attaching images so please bear with me.

On Dirty Coconut's thread about Lava rock mounts there was a brief mention about mounting on conch shells, which sparked an idea of a potential mount for a possible future Haraella retrocalla.

I got good advice from estación seca regarding shell mounts, but I'm not sure if what I have in mind would work.

My five year old brought this up to me while we were on the beach and said "this is 'specially for you Mama, please keep it always", so of course, I must keep this always. I was just thinking he would get a kick out of seeing a plant in it.

What do you think? It is very smooth but very cuppy (?) I think it could hold a little clump of moss maybe? I am wanting to ultimately put it in a small terrarium where I will hopefully have a better chance of keeping it moist.

Please see below: