According to the USGS (US Gov), above and below ground 244,000 metric tons have been discovered.

https://www.usgs.gov/faqs/how-much-gold-has-been-found-world

I believe we will never know the true amount as Gold has been mined for 1000’s of years and no record has been kept in the early years.
China mined a lot of Gold prior to the rise of European Civilization/ Roman Empire.

(I posted this earlier. The book appears to be well documented))
After reading “Gold Warriors” by Sterling and Peggy Seagrave (2003)
the amount of Gold that the Japanese had plundered from the roughly 15 countries in China and SE Asia could have been 200,000+ metric tons and most was hidden in tunnels in the Philippines and some brought back to Japan by 1945. This amount of Gold has been kept secret by the Allies, especially the US. When the OSS was disbanded, the CIA was born. The Nazi and Japanese Gold was seized clandestinely by the CIA to use as a slush fund to enable regime change with off book funds for decades. No one knows how much is still controlled by them.

Much of the hidden Philippine Gold, gems and other valuables were retrieved by the Marcos family for their own personal use.

It may be possible that there are 500,000+ metric tons above ground in 2024. We will never know. Even so, Gold is still the premier asset class.

Something along the lines of the Diamond cartel controlling the supply of cut diamonds on the market to create scarcity.