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#Introduction  Rocks are the primary source of all plant nutrients, except nitrogen. These nutrients are bound into a variety of crystalline structures (minerals).   Minerals are either formed during rock formation from magma (primary mineral) minerals)  or formed during soil formation (secondary minerals). Secondary minerals are formed when the local soil solution is saturated in respect to that mineral. In contrast to secondary minerals, primary minerals are formed in the earth mantle at high temperature and pressure.   At the earth surface these minerals may be thermodynamically unstable, and will eventually dissolve completely.   This dissolution process is extremely slow for most minerals. It has been estimated that it takes more than 30 million years to dissolve a 1 mm diameter quartz grain under natural soil conditions \citep{Lasaga_1984}.  
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Moreover, the weathering of Ca- and Mg-silicate minerals play a central role in the global carbon cycle.   The Ca and Mg, released by the weathering process, will be locked up as carbonates in marine sediments \citep{Sundquist_1985}.   On the long-term, atmospheric CO2 CO₂  is regulated by the weathering rates of these minerals, which is influenced by climate and mountain uplift \citep{Berner_2003, Raymo_1992}. The vast amounts of nutrients locked in soil minerals has triggered, nearly 100 years ago, the question if plants can  actively enter this potential nutrient source \citep{HALEY_1923,TURK_1919}. Five decennia decades  later, studies appear on the role of microorganisms, including mycorrhizal fungi, in mineral weathering \citep{WEBLEY_1963,DUFF_1963,Sperber_1958,Boyle_1967,Boyle_1973}. More recently, a publication with the provocative title *Rock eating fungi* appeared in Nature \citep{Jongmans_1997}.   This publication presented evidence of, presumably mycorrhizal, fungal hyphae drilling their way (chemically and/or physically) into feldspar grains.   This paper initiated renewed interest into the topic.   A series of reviews has been published since then, covering the research up to 2009 \citep{Finlay_2009,Hoffland_2004,Landeweert_2001}.  Since 2009, more evidence of mycorrhizal weathering has been published, based on *in vitro* and microcosm based research.   A new aspect is the effect of the arise emergence  of different types of mycorrhizal fungi during the evolution of land plants on mineral weathering rates, and thus the global carbon cycle. The gap between laboratory based studies and the real world has been bridged by a number of field based studied and mathematical modeling.   So far, evidence of a substantial role of mycorrhizal fungi on soil mineral weathering has been missing, while modeling studies show contrasting results.