MrBreeze911
Active member
Thats a good question. I found this on rockdustlocal.com FAQ page:Don't they need to be more specific about the chemical composition of the rock dust ?
There's hundreds of different rock dusts that one can find.
Many more that are made.
Do they always use one specific chemistry of rock to get the agricultural rock dust from ?
Q: Which Type of Rock Dust Should I Choose?
A: After nearly 25 years evaluating and working with rock dusts from all over North America we feel the best rock dusts for soil remineralization are volcanic geologic materials such as the Basalts and Metamorphic and Sedimentary types characterized by a rich diversity in minerals. This is how we came to define the BEST; as the Broad Elemental Spectrum Tectonic. Tectonic means "forces which shape the earth". Examples of these are found in the regional Volcanic magmas, such as the Pioneer Valley Basalt found in New England, regional Schists and Shales such as the Ashfield, Greenstone, St. George Black, and regional Clays such as the Diatomite/Montmorillonite, containing a diversity of nutritive materials, including volcanic magma and ash, diatoms, silicates, carbonates, humic and carbonaceous compounds. There are many clay-like geologic deposits being mined in the western regions for soil amendments and industrial uses, some have become famous marketed under trade names such as Azomite. Sand and gravel placers can also be very rich and diverse, such as the glacial moraines and the alluvial loess and silts. There are also the exotic and rare prospects with unique attributes. We introduced the Ruby MT Feldspar/Hornblende for its unique geologic profile from the roots of the Adirondacks with its content of silica, and gem garnet fractions sought after by BioDynamic growers, with subtle optic and piezo resonance and slow release nutritive properties. Paramagnetism is a magnetic attribute with quantifiable positive effects on plant growth found in high quality rock dusts. The volcanic Zeolites are commodity minerals with special electrical properties such as cation exchange capacity, used for filtering and mitigating toxicity in soils and water. Rich reactive liming materials such as the Wollastonite, a form of Calcium Silicate, and the Carbonatite, a volcanic carbonate-rich magma are found in rare economic deposits. Concentrates rich in individual elements such as Phosphorus are found in sediments such as the famous Tennessee Brown Rock Phosphate. Lignite, a form of brown coal, contains both carbon and humic substances and its extracts are a growing favorite among traditional organic farmers and indoor horticulturalists. Historically, the Granites have been favored by fruit and potato growers because of the potassium content and regional availability. "Bread From Stones" published by Julius Hensel in the mid 1800's, focused on Granite as one of the valuable "local rocks for local crops" at term coined by Prof. Peter Van Straaten. In short, there are a variety of useful and unique geologic materials in many locations, and we try to offer these in economic supply whenever possible. See the Store, Catalogs, and the BioChar pages for our current selections.