N.J. Stat. § 54:32B-8.32
Receipts from the sales of gold or silver and storage thereof, in the form traded on any contract market or other board of trade or exchange licensed by the Federal Commodity Futures Trading Commission as defined in the Commodity Exchange Act, as amended are exempt from the tax imposed under the Sales and Use Tax Act; provided that the sale shall have been in fulfillment of the obligations of a contract for future delivery of gold or silver, or an option to purchase or sell such commodity, entered into on and in accordance with the rules of such licensed contract or options market; provided, further that this exemption shall not apply with respect to any gold or silver subsequently converted to use by a purchaser and in such event such purchaser shall be liable for the sales and use tax imposed thereunder.
N.J.S. § 54:32B-8.32