Yep, too much calcium. Are you using calcium with or without D3? This happened to my chameleon when I was mistakenly dusting her food with calcium with D3.
Calcium with D3 should only be used twice a month while calcium without D3 should be used at nearly every feeding. It doesn't necessarily have to have D3 in it to cause excess calcium to be excreted though. The crickets should not look like ghosts when dusted, the coating should be very light - just enough to see it there. Excess excretion could mean that you are dusting your feeders too heavily.