Hello!

This is only the second time I post here.

I've found out that Spain (where I live) has the most important quarries for granite. Also while navigating in internet, I've found different stone industries that sell marble and slate. Are those two good remineralizers?
If I'd know more about it and its uses in agriculture, I could ask them if they'd send me some by-product, I mean rock dust

I'm looking forward to do some experiments with rock dust as soon as I get some!

Hi Mika,

From reading a earlier Forum posting on two, Andrew Clements has had tremendous success with rock dust in Greece. He also asked about marble. I will try to track him down for an update. I will get back to you on that. It is worth reading his posting because he is so enthusiastic about his results and was able to get a lot of information from the local quarries.

I am not sure about slate and it would be great to see if you can find a fine material to test and check with them to see if they have a mineral analysis. My thoughts are that it would be a good material to use with a fast weathering capacity, which means that it would break down in the soil quickly. Perhaps you can get samples of the three materials and do some trials. That would be great because based on the results we could think about that as far as a remineralization strategy for Spain.

I would like to informally say here how happy we are to have you as our International Coordinator for Spain and we greatly look forward to working together to get the word out there and initiate projects. I particularly look forward to this as I lived in Spain for ten years and love this country so very much!

Another informal thank you for your contribution of translating our website into spanish!

I look forward to getting our International Coordinator page up on the website soon.

Joanna Campe
Remineralize the Earth

I recall a report coming out of a small-scale trial of using marble rock dust in Nepal, perhaps mentioned in Soil Remineralization newsletter in the 1980s, that it seemed to have negative effects on plant growth, no clear reason being evident. I don't know of any further experiments with marble dust. As for slate, it may—for a single rock type—provide a broader spectrum of elements, which is what we seek when looking for natural mixed rock/gravel deposits. Here is an excerpt on slate composition from Wikipedia.com:

Chemical composition

Slate is mainly composed of quartz and muscovite or illite, often along with biotite, chlorite, hematite, and pyrite along with, less frequently, apatite, graphite, kaolin, magnetite, tourmaline, or zircon as well as feldspar. Occasionally, as in the purple slates of North Wales, ferrous reduction spheres form around iron nuclei, leaving a light green spotted texture. These spheres are sometimes deformed by a subsequent applied stress field to ovoids, which appear as ellipses when viewed on a cleavage plane of the specimen.

~Don Weaver

Mika,

As our coordinater for Spain you are already making such a contribution, I would like to ask you to do some demonstration trials and test these different materials. It is very important for the Mediterranean region to know whether we could use marble and/or slate. I don't think we should go on hearsay. You have the means to do the demonstrations, and we've are excited to see the results!

Joanna Campe
Remineralize the Earth