14. Name five minerals which do not contain oxygen. Where does
_fluor-spar_ occur? What is the element that enters most largely into
the composition of the earth's crust?
15. Name the forms under which the mineral _quartz_ occurs. Name some
of the oxides of iron. What is _iron pyrites_?
16. Name two _sulphates_. Name two _carbonates_. Name some of the
_silicates_. In what kinds of rock is _augite_ found? Where does it
never occur? In what kinds of rock does _hornblende_ usually occur?
Mention three species of felspar. What is one of the most
distinguishing characteristics of mica? Name three silicates of
magnesia. Mention some of their distinguishing peculiarities. Where do
_zeolites_ commonly occur?
17. What is a _quartzose conglomerate_? What is a _calcareous
conglomerate_?
18. What is _grit_? What is _freestone_? To what are the various
colours of sandstone due? What is _shale_?