Yesterday, this coin arrived from Paris: EARLY MEDIEVAL, Anonymous. Denomination: AR Sceatta (Series J, type 85), minted: Anglo-Saxon; 710-725, York Obv: Diademed head right, double strand pearl diadem Rev: A bird on a cross, pellets in field in front of bird and below horizontal bar on the cross; annulets at the ends of the horizontal arms, beaded inner circle Weight: 0.98g; Ø:10.8mm. I was able to track the provenance to 2014, which showed how the patina developed over the last seven years: Gallery 51 (May auction, lot 185, 30.05.2014) iNumis (Auction 42, lot 191, 05.06.2018) The dramatic blue colour, esp. on the obverse, made me a bit suspicious of artificial patination. However, on close inspection, minor dirt deposits are visible, showing the same vibrant colours underneath: This coin is an upgrade for this coin: Show me your coins with fabulous colours!
This coin was actually characterized by an "expert" auctioneer as an off-center strike which was not worthy of collecting. He then offered to consign it in his auction and advised me to buy a better example.
The style, condition, and toning vastly outweigh the minor level of off-center in my eyes. Congratulations!
The coin pictured below I won at a Roma auction. I removed the coin from the Roma slab & put it in a small cardboard box with 2 other coins that I intended to send to NGC for slabbing. I was under a lot of stress at the time & forgot about the 3 coins. Many months later I found the cardboard box & this is what the coin looked like many months later . Eventually it did go to NGC .
I guess my favorite ancient, in terms of bright toning, at least in part, along with a pleasing design and strike, would be my Syracuse tetradrachm of Agathocles. I've had this coin for decades, stored in a paper envelope and polyliner. Here's an owl that I have owned since the mid 1980's, the first one I ever purchased. This coin has been stored in a cotton-lined paper envelope. It has not been in contact with any sulfur that might be present in the paper, so it has acquired a basically even gold color with a little very dark blue here and there.