Basalt rock dust as soil amendment

[islandguy]

Bought some fill dirt from local rock crusher. Was their cheapest off grade, dust and bigger pieces. Their main product is a bluish colored gravel. The fill dirt is black when damp and grey when dry. I’m guessing it’s basalt. Anybody familiar with this? And is it a useful soil amendment if it is basalt? Seems promising looking at the studies I could find on line. Thanks

[drtreelove]

Not sure about your rock, but I would think a course grade like that is best as fill.  As for soil amendment, whether its volcanic basalt, granite or glacial, the finer the grind the better. Rock dusts are valued for their trace minerals content, and some basalts have high paramagnetism. 

 

Soilminerals.com guru Michael Astera uses glacial rock dust/paramagnetic basalt in his awesome COF, Agricola's 

4-8-4 (complete organic fertilizer). Thailand based organic grower materials supplier bonemeal.net now carries a glacial rock dust I believe. 

 

https://geology.com/rocks/basalt.shtml

 

https://www.remineralize.org/a-rock-dust-primer/