Question

Statement: Valuable gemstones such as rubies and sapphire contain aluminium oxides along with traces of transition metals as impurities.

State whether the given statement is true or false.

• A. True
• B. False

Answer 1

The correct option is A True

Sapphire is a gemstone, a variety of the mineral corundum, an aluminium oxide. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colours.

The only colour which sapphire cannot be is red – as red-coloured corundum is called ruby. Rubies are crystalline forms of aluminium oxide, which are red due to the presence of chromium as an impurity.

A rare variety of natural sapphire, known as colour-change sapphire, exhibits different colours in a different light.

The colour-change effect is caused by the interaction of the sapphire, which absorbs specific wavelengths of light, and the light source, whose spectral output varies depending upon the illuminant.
Transition-metal impurities in the sapphire, such as chromium and vanadium, are responsible for the colour change.

Hence, the given statement is $\text{true}$