Who’s ready for a thread on gold? Let’s do this!

1. Gold was one of the first metals that humans figured how how do stuff with bc it was shiny, pretty, malleable, and doesn’t tarnish or corrode.

2. Although gold has been mined for a very long time, most (like 90%) of the total gold mined has only been mined since 1848

3. 1848 is the year that gold was found at Sutter’s Mill in California, jumpstarting the California Gold Rush. But that wasn’t the first gold rush in the US- that honor belongs to North Carolina (with another small rush in Georgia before the one in California)

4. While the miners of the past where mining gold they could see, much of the gold mined today is too small to see with just your eye

(My husband just asked me why I’m not doing a fact a day. Well, I HAVE MORE FACTS THAN DAYS LEFT IN MINCUP AND THEY MUST BE SHARED)

5. In the US, 38% of gold goes to make jewelry and 34% goes into electronics. The rest goes things like gold coins, gold bars, and stuff

6. Gold is really heavy and a typical gold bar is 400 troy ounces (12.4kg or 27.3lbs), so all those movies where they easily carry off loads of gold bars? Implausible.

7. The two biggest consumers of gold are China and India

8. Gold nanoparticles are used to help treat cancer

9. Gold is in all cell phones and also in other electronics bc it doesn’t corrode. It’s also in computer chips

10. Mercury easily makes an amalgam with gold so it was used in the past to help get gold out of rocks. But since mercury is super toxic, mining companies switched to other things. It is still used by some artisanal miners though.

You can watch mercury and gold make an amalgam here

11. When the gold in an ore rock is very tiny, cyanide is used to dissolve the gold into a solution (a process called cyanidation) and then later collected using carbon. But this process only works if you don’t have impurities (like arsenic) in the ore

12. Thiosulfate is used instead of cyanide when the ore has lots of carbon or copper that would cyanide leaching difficult

13. Sometime the gold is so tiny, it’s found inside other minerals (like pyrite) and you have to do some extra steps to get the gold out. This type of ore is called “refractory ore”

14. Most of the gold mined in the US comes from Nevada- where a lot of the gold is refractory. These deposits are low grade and large tonnage which means they have to mine a lot of rock to get a small amount of gold

15. Gold is found in a lot of different types of deposits that formed in lot of different ways. Most of them involve hydrothermal fluids (really hot water moving underground) but not all, so there is no easy answer to how gold deposits form!

(That’s my way of saying never ask an ore geologist how gold deposits form unless you have A LOT of free time to hear the answer)

16. Sometimes gold is the main ore being mined, and sometimes it’s a (very profitable) byproduct. It depends on the mine. For example, Bingham Canyon mine is a copper mine that also has lots of gold (and molybdenum)

17. China produces the most gold of any other country. It’s followed by Australia, Russia, USA, and Canada.

18. Last week, Barrick Gold Corp. announced that it is purchasing Randgold Resources Ltd. to become the largest gold producing company in the world. Randgold sold for $6 billion. This move makes Barrick worth $18 billion.

19. Mponeng mine is the deepest mine in the world. This gold mine is located in the Witwatersrand Basin in South Africa, and it’s deepest parts are more than 4km below the surface! And it’s seriously hot at those depths!

20. Gold doesn’t join with many elements to make minerals, but it does occasionally like tellurium and they make calaverite. Sometimes, they let silver join in to make other telluride minerals.

21. Electrum is a naturally occurring alloy of gold and silver (with some other elements like copper and platinum thrown in there). Electrum is pale yellow to whitish in color depending on the proportions of gold and silver.

22. An old timey and pretentious way to say “contains gold” is to say “auriferous” and it’s also one of my favorite words. Aurum is the Latin word for gold. Aurifer was the Latin word for “contains gold” and people from the 17th century added -ous for fun

24. The largest gold nugget ever found was called the Welcome Stranger and was found in Australia in 1859. It was huge and weighed 78kg! But sadly, they melted it down

25. Recently, some spectacular large gold samples came out of the Beta Mine in Western Australia. Samples like this are very rare!
http://www.abc.net.au/news/2018-09-10/rich-gold-seam-half-a-kilometre-deep-in-kambalda/10219576

26. The helmets on space suits have a thin layer of gold to protect an astronaut’s eyes from harmful infrared radiation (while still letting visible light through)

27. Adding other metals to gold changes its color depending on what’s added. Rose gold is made by adding copper. White gold is created by adding a white metal, like nickel or palladium.