The jewlers company name is shariffs. I just got off the phone with them. The instrument they used is brand new. And cost over $18,000.00 the owner said that the device could read in the mils. Any kind of metal. He said if there. Were any small amount of stainless. Zinc magnesium nickle or anything it would have read it . Its atomic metal signature was fe; which stands for iron fith no trace elements.