Question

Silver glance or argentite is the ___________.
A) Sulphide ore of silver
B) Carbonate ore of silver
C) Halide ore of silver
D) Silicate ore of silver

Answer 1

Argentite is a black-grey cubic silver-sulphide mineral. It is an important constituent of silver ore and contains almost 87% silver and around 12.94% sulphur. The chemical formula of argentite is $A{g_2}S$. Argentite is also known as a silver glance. So, I hope now you get an idea of the correct option.

Complete step by step solution:
Argentite is the most important silver ore after galena. Galena is a lead ore that contains silver( about 1%). Argentite has a chemical formula $A{g_2}S$, silver sulphide and thus, it is a sulphide ore of silver. Its molecular weight is 247.80 g. It contains silver – 87.06% and sulphur- 12.94 %. It has an isometric structure and is stable only at temperatures above 173 degree Celsius. Its colour is lead-grey to black. The Argentite word comes from the Latin word for silver, Argentum, from which the chemical symbol for silver, Ag, is also derived. Its lustre is metallic. Its crystals are opaque. It is sectile, meaning it can be cut with a knife like lead and fresh shiny surfaces will eventually form a dull coating after prolonged exposure to light. Argentite is also known as silver glance because it contains silver in large amounts and another constituent than silver is sulphur only.

Therefore, argentite or silver glance is the sulphide ore of silver. Thus, option A is the correct answer.

Note: Argentite can only exist at high temperatures like ${\text{17}}{{\text{3}}^{\text{o}}}{\text{C,17}}{{\text{7}}^{\text{o}}}{\text{C or 17}}{{\text{9}}^{\text{o}}}{\text{C}}$. When argentite cools to ordinary temperature, it turns into its monoclinic polymorph called ‘acanthite’. Thus, we can say that argentite is the high-temperature form of acanthite. Sulphide of silver (argentite) also called vitreous silver or silver glance.