Indentation is a technique used to determine the mechanical properties of a specimen. In this project we are investigation the Mohs Hardness Scale.  This scale was originally developed for quick field identification of minerals.  As such, it is intrinsically qualitative, thus does not correspond directly to any one mechanical property.  In order to quantify mechanical properties, other methods are required.  Three properties that influence Mohs Hardness are: modulus, E, (resistance to elastic deformation); hardness, H, (resistance to plastic deformation); and toughness, T, (resistance to fracture).  Our project also includes the study of garnet and its toughness.  Toughness is important to determine how garnet fractures under conditions of pre-existing cracks, vis. How garnet fractures in the natural environment.  Since garnet is found in  metamorphic rocks, this knowledge of microfractures lends itself to a greater understanding of tectonic problems.  Through collaboration with the Chemical Engineering Material Science Department, mechanical properties have been calculated by use of microindentation and depth-sensing indentation "nanoindenation."

The preliminary modulus data show that our nanoindentation data corresponds closely to the published literature.
 
 
 

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