The chief impurity present in red bauxite is:

Which mineral was used in the isolation of radium?

An important oxide ore of iron is

Select the correct option using $T$ (true) or $F$ (false) for the following statements:
$(1)$ Calamine and Siderite are carbonate ores.
$(2)$ Zinc blende and Pyrite are sulphide ores.
$(3)$ Haematite and Magnetite are hydroxide ores.
$(4)$ Malachite and Cuprite are copper ores.

Which of the following ores is called malachite?

The main ore of aluminium is: