The book value of gold is currently $42.2222 per troy ounce

"Gold held "under earmark" at Federal Reserve Banks for foreign and international accounts is not included in the gold stock of the United States; see table 3.13, line 3. Gold stock is valued at $42.22 per fine troy ounce."
https://www.federalreserve.gov/data/intlsumm/current.htm

"The book value of gold is currently $42.2222 per troy ounce."
https://www.fiscal.treasury.gov/reports-statements/gold-report/

"The statutory price of gold is set by law. It does not fluctuate with the market price of gold and has been constant at $42 2/9, or $42.2222, per fine troy ounce since 1973. The book value of the gold held by the Treasury is determined using the statutory price."
https://www.federalreserve.gov/faqs/does-the-federal-reserve-own-or-hold-gold.htm

"Book Value: The Department of the Treasury records U.S. Government owned gold reserve at the values stated in 31 USC § 5116-5117 (statutory rate) which is $42.2222 per Fine Troy Ounce of gold. The market value of the gold reserves based on the London Gold Fixing as of September 30, 2020 was $493.4 billion."
https://www.fiscal.treasury.gov/reports-statements/gold-report/21-02.html

"The Official Price of Gold is Only $42.22/oz.
For many decades now Americans have been allowed to own gold and silver and, despite gold and silver trading in the vicinity of $1200/oz. and $18/oz. respectively, the “official” price of gold is still $42.22 per ounce.

As such, all holders of gold bullion coin should take the “official” price of $42.22 per oz. very seriously when accumulating gold for protection"
https://www.mining.com/beware-official-us-government-price-for-gold-is-only-4222oz/