After a certain amount of time (I think its like a day or more) It transforms from that raw chunk of rock and crud, to that shiny little spire... In raw form, I've never seen it make anyone sick... Only when it's transformed into a spire form, or if you've CUT it into some pretty little shape thingo, does it make your person sick...
*Opens a fancy bookie and slaps on scientist glasseseseses*
Ahem... Tiberium is an alien substance which absorbs its surroundings and grows, becoming more awesome... Meaning if you planted Tiberium next to a field of gold, iron, copper, or even a tree with fruits on it, then it'll absorb all of their properties... Because of this, Tiberium can be virtually turned into any mineral (Valuable building material, resources for energy) Through the right processing... It doesn't mean your brand new car will be a glowing green, they simply extract the safe minerals from the inside...
The way Tiberium absorbs things rapidly can be a path to death... If you had tiberium on your person, then it would eventually mold onto your skin... Through a series of months, it'll make its way through your cells to your blood stream...
Because of the awesomeness of the Tiberium, you will gain such things as a longer life, stronger muscles, a healthier body, basically because of the Tiberium absorbing nutrients, and your body uses it like a baby sucking on a mango...
Long story short, you will eventually BECOME tiberium... Meaning you won't be able to move... If you're lucky, your heart or your blood will crystalize before the rest of your body, and you'll die...
(Back to Sims 3) I've never had my sims die from Tiberium in their inventory... I'll keep on going and see what happens...
If they turn into a sim-sized Tiberium spike, and sell for millions, then I'm gonna have a lot of fun with the neighbours