An 1855 Wass, Moliter and Co gold $50 coin is to auction with a valuation of $10,000-15,000 at Doyle in New York on November 11.
The largest denomination coin produced by the firm and the most valuable private issue coin to circulate in the US, the $50 issue was produced by a pair of Hungarian immigrants in San Francisco during the California gold rush.
Very few are extant, many having been smelted due to their high gold content.
A gem uncirculated strike from the Garrett collection achieved $345,000 at Stack's Bowers in 2003.
A group of five 24k Chinese gold rounds, marked "King Fook Bullion Dealer", are estimated to make $7,500-10,000.
The lot adds up to a combined 10 troy ounces.
A large azurite deposit discovered in the Toussit region of Morocco is estimated at $7,000-10,000. A portion of the azurite has been replaced with malachite - a rare natural occurrence known as pseudomorphism.
A fluorite rough and cut stone argentiere glacier could realise $7,000-10,000. Found in Chamoix, France, the specimen is a translucent pink and features octahedral-shaped crystals.
Mineral deposits can realise impressive figures on the current market. A recent sale at Heritage Auctions saw a large purple fluorite deposit achieve $125,000.
We have a range of rare coins available to purchase.
Sign up to our free weekly newsletter for the latest from the world of collecting direct to your inbox.