DOLERITE

 

 

Type of Rock: Magma: Texture: Mineralogy:
Igneous rock Intrusive (doesn't reach the surface) cool at low temperatures. Aphanitic (fine grained) to phorphyritic (large crystals embedded in the groundmass) Dominant mineral: Pyroxene and plagioclase with larger amounts of pyroxene than plagioclase or equal amounts of both.

THIN SECTION

A thin section is made by grinding down a slice of rock which has been glued to a glass slide until it reaches a thickness of about 0.03mm (30 microns). At this thickness most minerals become more or less transparent and can therefore be studied by a microscope using transmitted light.

 

Back to rocks of Famous Monuments

 

© Guillermo Rocha, P. G. / Brooklyn College Geology Department