Way too many to list! you can test rocks with hydrochloric acid. If it fizzes, it leaches!
Yep, they are definitely flakey and leave sparkly specks all over the place. Mica schist it is! Thanks for helping me id these rocks! So then, is mica schist safe to put in the tank?Smeagol, Are your rocks super hard, or are they flakey and leave sparkly specks on your hands when handling them? They are definitely metamorphic rocks based on the foliation (parallel alignment of mineral layers or banding of different colored minerals). If the rocks are super hard, they're most likely "gneiss". If the rocks are more soft, flakey, & leave sparkly specks on your hands, I agree with jrh and would say the rocks are a "mica schist".
Rats. I've actually had these rocks in my tank for about a week now. I'm going to remove them immediately. Do you think there's any permanent damage done?smeagol, i, personally, wouldn't put them in my tank. Schist is very prone to mechanical weathering, meaning the water will get in between the soft foliation groves and likely split them apart over a short amount of time. Mica schists are weird: Micas aren't exactly clay minerals, but they can act like them. They'll get all over your tank, some clays are "swelling clays", etc., and will definitely cloud your water. Not to mention the possibility of metallic minerals in the schist, such as pyrite (shout out to jrh), blah, blah, blah. If it gets all over your hands just by touching, imagine what it will do to your tank. Sorry, i could go on & on & on. I'm sure you figured out i'm a geologist (who talks way too much). Don't put them in your tank! Happy planting! Ebeth
Rats. I've actually had these rocks in my tank for about a week now. I'm going to remove them immediately. Do you think there's any permanent damage done?
What about the rocks that are commonly sold in fish stores as "petrified wood"? Is that stuff safe to use? I have a little bit of it that I could use to replace the mica schist? But it has a very clay-ey feel to it... Would I just be trading one evil for another?