A ferro-magnesian mineral. Dark green to black, although weathered specimens may look faded. Dull luster; blocky appearance; 87-93 degree cleavage, although it is typically hard to find or see.

 

Constructed of Single Chains Of Silica Tetrahedra, stacked in alternating rows, ionically held together by iron and magnesium ions. The cleavage forms from the way the cleavage skips through the single chains. 
    

This is a common mineral in mafic igneous rocks usually mixed with ca plagioclase.

 

 

 

A ferro-magnesian mineral. Dark green to black, although weathered specimens may look faded. Dull luster; blocky appearance; 90 degree cleavage, although it is typically hard to find or see. 
    

This is a common mineral in mafic igneous rocks usually mixed with ca plagioclase. We often want to confuse pyroxene with amphibole because they are both mafic minerals found in mafic igneous rocks but the amphibole is shiny black and shows abundant parallel cleavages.

 

 

 

A ferro-magnesian mineral. Dark green to black, although weathered specimens may look faded. Dull luster; blocky appearance; 90 degree cleavage (which can be seen in the view in this specimen, although it is typically hard to find or see. 
    

This is a common mineral in mafic igneous rocks usually mixed with ca plagioclase.