Where can I find a small, opaque, hermetically sealed jar?

Do you really mean hermetically sealed, or do you just mean stoppered?

i would prefer sealed, but if you have a good stoppered version, please share.

I don’t have any. I just wondered if the difference would affect your search results.

Larger bottles meant for canning are available. When properly sealed, they are sealed. You might find something similar at a canning supply house online. Good luck.

Here’s some 2-ounce minis.

Hermetic just means airtight, yes?
Glass: http://www.bedbathandbeyond.com/store/product/wean-green-reg-6-ounce-wean-bowls-in-blueberry-2-pack/1041530306
Glass: http://www.containerstore.com/shop/kitchen/foodStorage/jarsTerrines?productId=10005560&green=8D97E4E8-44A3-52D8-9DE0-410F3B3F2FC1
Glass: http://www.containerstore.com/shop/kitchen/foodStorage/jarsTerrines?productId=10011037&green=8D97E4E8-44A3-52D8-9DE0-410F3B3F2FC1

Opaque is the tricky part. These ceramics give exterior dimensions, not interior volume:
www.bedbathandbeyond.com/1/1/119960-oggi-3-piece-pear-shaped-mini-airtight-ceramic-canister-set.html