I decided to actually look at what you get when you call the Geo folks so here's what I found out.
Metals, minerals and crystals come in common, uncommon and rare and are valued accordingly. If you call the Geo they will tell you what they are made of. It will cost you $20 so do it. When you send them in to them they come back in two to four days changed into something more valuable. Metals come back as minerals.
Phozonite: When you send it to the Geo folks it comes as back as Phozone. It, and so far as I can tell, all the minerals have the ability to send out a Focusing aura. Phozone is valued at $80.
Ultranium: Original value is $65. I sold mine instead of sending it in so I don't know the new value. It is made only of Selium, so what you'll get back is probably Selium.
Ozinold: Valued at $65. Since it contains both Ozinate and Aleineat you may get back one of each or randomly one of the two. I'm going to research the ones I I sold with a new Sim or if I find them again so I'll know for sure.
Socialite: Valued at $30. Mostly Peryllium so this is probably the mineral you'd get back, but since it also contains Volenton there is a chance of getting that as well or instead.
Flamingonium: Value $30. Mostly Melacoo with some Peryllium.
Crytunium: Value $65. Mostly Volentom with some Crytacoo.
The crystal, Jonquillist, vallued at $30, had the ability to Energize. When it came back from Geo it was worth $80 and changed to Focusing Aura. It was originally Crytacoo and Phozone in composition and came back Crytacoo.
Why is this important? I don't know for sure it is, but if you are missing a certain mineral, with the information of what the original item is composed of, you'll be able to know what to send to Geo to get the minerals you are missing for your collection. Having them as free sources for emotions is pretty cool too.