The titanates are well marked in the mineral kingdom.
Ilmenite is isomorphous with geikielite, MgTiO 3, and pyrophanite, MnTiO 3; many of the "rare minerals" - aeschynite, euxenite, polycrase, &c. - contain titanates (and also niobates).
The titanates are very similar to the silicates in their tendency to assume complex forms, e.g.
Acid solutions of titanates are not precipitated by sulphuretted hydrogen; but ammonium sulphide acts on them as if it were ammonia, the sulphuretted hydrogen being liberated.
Similar is the behaviour of the fused dry salt at a dull red heat; it acts on silicates, titanates, &c., as if it were sulphuric acid raised beyond its natural boiling point.