So, I don't want to see this thread get buried...
The official Delta Chi Flag is a two pointed pennant bearing the letters delta and chi in buff on a red background with a buff border. MC, the vexillologist, could probably describe it in much more official terms than that.
(This picture makes the letters and border look more gold than they are, in person they are closer to true buff.)
This is the seal of the fraternity. Chapter seals will have the chapter name in place of the laurel leaves on the bottom of the seal.