Is there a specific level that Aidonium is available in mineral shipments at? I'm able to purchase it, but have yet to receive it in a shipment.

you can't purchase it until it has been received once.

I did not begin receiving it until somewhere in the level 160 range.

~Q

I think there is a hard cap at 160. I could be wrong.

You can have someone send it to you in order to be able to purchase it, and it will show up in the mineral list even if not received as is apparent to anyone who joined the game after the inclusion of the mineral.

Interesting though, 160...

that sounds about right...
once I got 1 aidonium at around 160~165,
it kept dropping 2~3 every time I claimed Mineral point.

In hindsight, it is definitely absolutely correct. I went from zero 30 or 40 times in a row with large samples to several an hour just from going over that threshold. Aside from voodoo and future changes by the almighty Dan, that is about it. I noticed how crappy Kurenite draws got weeks before any aidonium was mentioned on the forums. I went from 30m/hr back to 20m/hr then back up to 50m/hr. At 160 you also get to fight Graxis, it is quite the threshold in terms of potential awesomeness.

Agreed on all accounts. Also Exotic matter seems to be changing but that may just be my perception.

Aidonium showed up for me on the first shipment after I turned level 160. I got none at level 159 so it sounds like it becomes available at level 160.