Colorado's Purchasers of Valuable Articles law (C.R.S. 18-16-101 to 18-16-110) covers anyone in the business of buying items made in whole or part of precious metals or stones, including jewelry, household goods and gold and silver bullion, and anyone who buys five or more such items in 30 days. The buyer must see a Colorado driver's license or ID card, a photo driver's license from another state, a military ID, a passport or an alien registration card; a government ID without a photo works only with a print of your right index finger. No one under 18 may sell.
The buyer records your name, address, date of birth and ID number, plus a description of each piece by its marks, weight and design, and you sign the register along with a written statement that you own the items, how long you have had them and whether they were found. Records are kept three years, and a weekly report with your physical description and the price paid goes to local police and to the police where you live. Each piece is then held unaltered for 30 days. Stamped and assayed gold and silver bullion and gold coins skip the hold. Silver coins are not named in that exemption, so a shop may hold them the full 30 days. Pawnshops follow their own article, which also sets a 30-day hold on outright purchases (C.R.S. 29-11.9-103).
Breaking these rules is a class 6 felony for the buyer. The article sets no state license or payment-method rule; cities and counties may add stricter rules of their own.