I haven't discovered a lot of the cities yet, mostly north and east, but I haven't found a shop that seems to specialise in jewellery, which I keep picking up along the way. I have Warmaiden's in Whiterun for weapons, etc., and there are lots of places to dump food and ingredients, but nothing devoted to jewellery. Minor matter, but any thoughts?

General Stores are the best to sell jewelry. You should also consider the Merchant Perk, as it lets you sell anything to anyone.

The Khajiit traders also buy them. There are a couple of jewellers (Whiterun, Markarth, Riften) butmost of them have very little gold, which is rather strange.

I'm pretty sure court wizards buy jewelry as well.

Agreed. Especially later in the game, when everything you loot or craft is expensive. I also usually take the investor perk, to be able to get most merchants more gold.

Thanks for that. How do you get those two perks, merchant and investor?