Jolyon
Sorry, but I haven't used a readily availble commercial on-line translation program yet that was worth the powder to blow it to hell. The "translations" are just about meaningless.
I think it would take a field-specific translator, designed for mineralogy and geology. There are just too many "arcane" words that have no common language equivalents...
I had loads of fun trying to translate a paper on Laurion that was written in German, though. I can read a bit of German, so I got a lot of chuckles and some downright hoots out of the translations the program tried to feed me... :~}
Lots of luck finding something that actually works well enough to use here.
Best
Al Plante