Thanks guys!
I have been talking, and we(me and JD) decided to swap tortoises......i get to keep tiago and all of his tortoises too!
Don't tell JD yet he does not know!
I believe most of it is genetic. However, I have heard that environmental conditions play a big role. Specifically, leopards raised in warmer environments will grow lighter colored shells, and leopards raised in cooler conditions grow darker shells. Whether there is any actual documented truth or studies related to this I can't say any thing like that exists.