Vermiculite source in California

[wilef]

I haven't seen a lot of options for Vermiculite, though I haven't made a lot of calls to local garden centers yet. Two options I've seen are these from amazon and Home Depot. Anyone have opinions on whether these are good for the insulation base (to mix with cement)?

https://www.homedepot.com/p/Vigoro-2-cu-ft-Organic-Vermiculite-Soil-Amendment-100521092/205655205

https://smile.amazon.com/Coarse-Vermiculite-cubic-foot-bag/dp/B015RXB9HW/ref=sr_1_7?keywords=vermiculite&qid=1576883591&sr=8-7

[UtahBeehiver]

Look for perlite then, most supplier of concrete block (CMU) stock perlite to fill the cavities of concrete block for insulation.