_________ is heavy and dark in colour.

___________ are usually dome shaped with no definite floor.

On the basis of chemical composition,igneous rocks are classified into _____________.

__________ rocks are not crystalline.

___________ are also called primary rocks.

___________ have higher percentages of oxides of denser elements and silica content varies between 40 to 60 percent.

___________ were formed due to cooling,solidification,crystallization of molten material of the earth.

___________ are chiefly compsoed of granite and commonly form the core of mountain ranges.

___________ are smooth,crystalline and fine grained.

Based on their origin, the igneous rocks are classified into ________ types.