48x73s=3504
52500-3504=48996
55-48=7 crystals x [2minutes]= 840 crystals gain = 49836
-increase of 59 crystals = 11cry per sec
52500-49836= 2664 divided by 11 crystal per sec = 242.2 sec or 4minutes 03 seconds.
[6min 03 seconds]
might be wrong, but i was bored so i tried XD