Is the crystaline structure of a diamond not an inherent characteristic of carbon, given certain conditions?
Diamond is an unstable allotrope of carbon. In fact, diamonds will eventually decay left to their own devices, though not soon enough to bother re-writing the "diamonds are forever" line. Diamond is more structured than graphite, and has less entropy. The "specific conditions" required to create diamond from graphite are the application of energy and pressure. Without an external energy source, graphite won't become a diamond because it would be going against thermodynamics. Only local decreases of entropy are allowed, and even then only by expending much enthalpy. Biology works the same way. Under specific conditions (the application of external energy sources) biology can decrease entropy. Absent an external energy source, biology stops working.
The problem with the common argument from the creationist/ID camp is that biology can't evolve without violating thermodynamics. However, under the conditions necessarily premised for that to be true (no external energy sources), biology couldn't even survive.