Importing loose gems into the United States can be a very lucrative business. Like most other import products, gems are subject to a number of restrictions and taxes before they can be brought in to the country. Before you start, make sure that you are aware of the quality and source of your loose gems. There are a number of loose gem suppliers around the world and you should only go through a trusted, recommended supplier.
For your first shipment, contact a licensed U.S. Customs broker or freight forwarder. This person can assist in properly filing all of the paperwork, and help with shipping.
Research your product so that you can accurately appraise quality, source, type and value of the gems.
Become familiar with the the import regulations regarding your particular gemstones (this may vary from country to country). Refer to the United States Harmonized Tariff Schedule (USHTS) to determine the duty that is applicable to your gemstones.
Research General Note 3 in the USHTS to determine if gems from your particular source country apply for any special import programs.
Budget well for the import duty, as taxes on gemstones are generally quite high.