I can't check the undermine journal from this machine, so from memory:

Adamantite ore = 30g / stack
Primal Earth = 4g / single.

Mercurial adamantite = 4 adamantite dust + 1 primal earth.
1 stack Adamantite Ore = 4 adamantite dust.

So 34g (one stack adamantite ore + one primal earth) = one Mercurial Adamantite.

These sell for 95 to 115g each on my server.

Demand is limited mostly to those leveling jewelcrafting, so this would be an easy market to flood and crash. But, it's worked for me for the past couple days, netting a couple thousand gold for 10 minutes of "work".

You're welcome, aspiring jewelcrafters, for the soon-to-be-cheaper 10 points of the BC skill point grind.