I have to say that I have never found a group of 2 MMs - I thought they always occur as singles and triples. I have a few times been in one triple group and had the wavescanner signal for another MM in the distance.
re Arsenic - I had a thread about this so-called percentage composition figure given in the planet data and in the end I think it just means there might be some there if there is any figure, the actual figure meant diddly-squat it seemed.![]()
This spawning rate problem is really two-fold.
The rare mats are more likely to spawn in "rare" outcrops. And the outcrops are spawning not entirely by the RNG. Rather when you pick up an outcrop of a certain type, the same type of outcrop is more likely to spawn nearby. Translated into human language - if you're only picking up mesosiderites, you will generally find more mesosiderites, etc.. That is my experience.
Therefore - if you focus on metallic meteorites, which has the highest probability of arsenic, you will find out that the 2% composition/probability can be quite accurate and sometimes even exceed it. If you, however focus on different types of outcrops (It's tempting to shoot at everything that appears on your wave scanner, you might end up in a situation where you're only spawning lower-grade outcrops and finding NO arsenic whatsoever.