You can't alchemize fire gems without a LAB
Also, several people have suggested that one save up gold incase this exact type of event occurs, but you can't save up gold, there isn't a "1st Bank of Dominions" out there to store your gold for a rainy day.
The closest you can get is to alchemize fire-gems, which is exactly what you CANNOT do without access to a lab, you see?
It's a beautiful example of Catch-22