The reason for the high price is that the ingredients, (which are barely ever on the AH in high supply) are Scarlet Stones.
These drop at a pretty abysmal rate from Antlion's in Attohwa Chasm. Unless an alliance goes down to Farm HQ Antlion Jaws for Alastor Antlion (Rostrum Pumps) your not gonna see many scarlet stones for sale.
Most ppl who craft these more than likely farm the ingredients themselves, or sell the ingredients to a goldsmithing friend.
These sold from 10-20k apiece and then plummeted to 2k in a matter of 1 week. Why are people even making these anymore?
Dimi: Thanks! It sucks that I made quite a few before that happened and they are still in my inventory. SE is always trying to find a way to make Goldsmithing unprofitable :)
I don't get why the singles are sold for so much. At the time I'm commenting there haven't been any scarlet stones up for two weeks, but still... Only 5k to craft? When a stack isn't even twice the price of a single?