I just bought a large bag of vermiculite.
This is a grey black color,
whereas the vermiculite I bought in the spring was a beige color.
Does the color of the vermiculite mean different minerals?

not sure but I think that is the one they used for insulation .. check the bag to make sure there is no asbestos listed in it

http://www.manufacturersofverm...

Hmmm.... I've never seen that. What you want for plants is horticultural vermiculite. It's sold in garden centers, hydroponic shops, other garden sources.

I'm not at all familiar with the other kind. But that asbestos stuff was was outlawed in 1990
http://en.wikipedia.org/wiki/V...

Karen

This is labelled as Horticulture vermiculite.
I'll do some searches, and maybe quiz the Garden Center where I bought it.

I've also read in multiple places that no vermiculite sold in the last decade or two containing asbestos (like, that mine was shut down).

That might have included an assumption like "None sold in the USA".

I never saw dark vermiculite. I like the light color because, if I have a seed that needs light to germinate, but some vermiculite gets washed over the seed, the seed still gets enough light to germinate.

Vermiculite doesn't contain asbestos these days, even if it's 'insulation' vermiculite.
Because the price of insulation vermiculite is much lower than the price of horticultural vermiculite, I always use the insulation vermiculite ( about $ 25 for 100 liters). Usually the vermiculite I buy is beige, but I had once a darker color. There was no difference in germination at all.
I never used the horticultural vermiculite, but I doubt the germination will be better. It's just a commercial trick to ask more for the same product.
http://seedsite.eu/zaaiinstruc...

Thanks for the information Jonna!