(i) No, he was wrong. Pure gold is very soft and is, therefore, not suitable for making jewelry. It is alloyed with either silver or copper to make it hard. But, sometimes jewelers mix a large quantity of copper and silver in gold, to earn more profit.
(ii) Untrustworthiness, cheating, cunning.
(iii) We should always purchase the gold jewelry from a branded shop with proper receipt and Hallmark certificate.
(iv) Government insists on purchasing hallmarked jewellery as it contains the gold and its alloyed metal (i.e., copper or silver) in a fixed ratio.