[Molog]

Any mag in a lab gets the alchemy command.
There should be two-way and one-way arrows on the alchemy interface. Click on either side or use short cuts to alchemise.

All gems can be turned into or made from astral gems using a 2-to-1 ration. Earth gems can be alchemised into 10 gold and fire gems into 15.

The master alchemist pretender with its 100% alchemy bonus gets 30 gold for fire and 20 for earth. There is also a standard alchemist which you can find sometimes, but he only gets a 50% bonus.