Comment by jaclaz

Maybe it is a local (US) thing, here in Italy/Europe you can find black olives in glass jars just fine, a few examples:

http://www.polli.it/prodotti/olive/olive-nere-denocciolate-v...

http://shop.oliosalvagno.it/vasetto-olive-nere-in-salamoia-g...

https://pietrasantaaltosalento.it/it/home/19-olive-nere-in-s...