Difference Between Gold and Pyrite

Main Difference – Gold vs Pyrite

Gold and pyrite are very important inorganic substances that can be found in nature. Gold is a metal that is very unreactive. Therefore, it occurs as a free element in nature. It is very valuable due to its lustrous yellow appearance and many other properties such as malleability. Pyrite, on the other hand, is a mineral. It is also known as fool’s gold since resembles gold. Although they look similar, gold and pyrite are very distinct substances. The main difference between gold and pyrite is that gold is a chemical element having the symbol Au whereas pyrite is a mineral having the chemical formula FeS₂.

Key Areas Covered

1. What is Gold
– Definition, Chemical Properties, Uses
2. What is Pyrite
– Definition, Chemical Properties
3. What are the Similarities Between Gold and Pyrite
– Outline of Common Features
4. What is the Difference Between Gold and Pyrite
– Comparison of Key Differences

Key Terms: Aqua Regia Reagent, Fool’s Gold, Isotope, Mineral Streak, Noble Metal, Gold, Oxidation State, Pyrite

What is Gold

Gold is a chemical element having the symbol Au and atomic number 79. The atomic weight of gold is 196.96 amu. Gold has a lustrous yellow appearance. Gold is a metal and has exceptional properties that have made it a very valuable substance. The electron configuration of gold is [Xe] 4f¹⁴ 5d¹⁰ 6s¹. Gold is in the d block of the periodic table and is a transition metal.

At room temperature, gold is in the solid state. The melting point of gold is 1064.18 °C and the boiling point is 2970 °C. Gold is one of the densest metals on earth. The specific gravity of gold is 19.3 (at 20^oC). It is a good heat and thermal conductor. Gold is highly malleable and ductile. We can form extremely thin gold sheets known as gold leaf. These sheets may even be semi-transparent.

Figure 1: Gold

Gold does not tarnish or corrode. Although it is resistant to many strong acids, it dissolves in aqua regia reagent (a mixture of nitric and hydrochloric acid). Gold has only one stable isotope. It is ¹⁹⁷Au. This is the only naturally occurring isotope of gold. However, there are radioactive isotopes that have been synthesized.

Gold is highly unreactive, thus is named as a noble metal. However, it can form some compounds under specific conditions. The most dominating oxidation states of gold in those compounds are Au(I) and Au(III). The Au(I) ion is known as aurous ion and the Au(III) is known as auric acid. Anyway, gold does not react with oxygen at any temperature.

There are many applications of gold; for example, the production of jewelry, production of corrosion-free electrical conductors, medicinal purposes (tooth restorations), etc.

What is Pyrite

Pyrite is a naturally occurring mineral that is an iron sulfide given by the chemical formula FeS₂. It is also known as fool’s gold since it resembles gold. Pyrite is the most common sulfide mineral among other sulfides.

Figure 2: Pyrite

The formula mass of pyrite is 119.98 g/mol. The crystal system of this mineral is isometric. The streak of pyrite mineral is greenish black to brownish black (The streak of a mineral is the color it displays in finely powdered form). Pyrite has a brass-yellow color and a metallic luster. This substance is opaque.

The specific gravity of pyrite is about 4.9-5.2. Therefore, it is comparatively less brittle. Although pyrite is composed of iron and sulfur elements, pyrite does not serve as a considerable source of either iron or sulfur. The most important use of pyrite is as an ore of gold. Gold and pyrite form under similar conditions and occur together in the same rocks. Therefore, gold can be obtained through pyrite mining.

Similarities Between Gold and Pyrite

Gold and pyrite both have a metallic luster and a yellowish, bright appearance which resembles each other.

Definition

Gold: Gold is a chemical element having the symbol Au and atomic number 79.

Pyrite: Pyrite is a naturally occurring mineral and an iron sulfide given by the chemical formula FeS₂.

Occurrence

Gold: Gold occurs as a free element in pyrite ores.

Pyrite: Pyrite is a naturally occurring mineral.

Specific Gravity

Gold: The specific gravity of gold is 19.3 (at 20°C).

Pyrite: The specific gravity of pyrite is about 4.9-5.2.

Molar Mass

Gold: The atomic weight of gold is 196.96 amu.

Pyrite: The formula mass of pyrite is 119.98 g/mol.

Conclusion

Gold and pyrite are two inorganic substances having similar appearances. Due to this reason, pyrite is also known as fool’s gold. Gold is a high cost, valuable substance. The main difference between gold and pyrite is that gold is a chemical element having the symbol Au whereas pyrite is a mineral having the chemical formula FeS₂.

Reference:

1. “Gold.” Wikipedia, Wikimedia Foundation, 16 Jan. 2018, Available here.
2. The Editors of Encyclopædia Britannica. “Gold.” Encyclopædia Britannica, Encyclopædia Britannica, inc., 8 May 2017, Available here.
3. “Pyrite.” Wikipedia, Wikimedia Foundation, 15 Jan. 2018, Available here.

Image Courtesy:

1. “GoldNuggetUSGOV” By Unknown -(Public Domain) via Commons Wikimedia
2. “Pyrite-278315” By Rob Lavinsky, iRocks.com – (CC BY-SA 3.0) via Commons Wikimedia