A Royal Affair: The Chemistry of the Crown

Introduction: A Coronation Fit for a King

As the nation eagerly awaits the coronation of King Charles III this today, there's one aspect of the ceremony that captures everyone's attention - the stunning royal crown. But have you ever wondered about the chemistry behind this regal masterpiece? In this blog post, we'll look at the chemistry of gold and precious gemstones to uncover the chemistry of King Charles III's crown.

Refining Gold: From Ore to Pure Gold

Gold has long been associated with royalty, and it's no surprise that it forms the basis of the royal crown. Pure gold, or 24-karat gold, is obtained through a process known as refining.

Refining gold involves several stages of chemical and physical processes. Gold-bearing ores are first crushed and ground into a fine powder. The gold particles are then separated from the other minerals using a method called froth flotation. In this process, the gold-bearing minerals are coated with a hydrophobic substance, allowing them to attach to air bubbles and float to the surface[1]. The gold-rich froth is then collected, dried, and smelted to form a gold alloy. The gold alloy is then subjected to further purification techniques, such as the Miller process, where it is treated with chlorine gas to remove impurities like silver and base metals, leaving behind pure gold[2]. Gold is highly valued for its resistance to corrosion, its malleability, and its beautiful luster.

Gemstones: The Chemistry of Sparkle

The royal crown is adorned with a dazzling array of precious gemstones, each with its own unique chemical properties. Here's a closer look at some of the most famous stones featured in the crown:

Diamonds: Nature's Hardest Substance

Diamonds are composed of pure carbon atoms arranged in a crystal lattice structure. They form under extreme heat and pressure deep within the Earth's mantle and are brought to the surface through volcanic eruptions[3]. Diamond's hardness comes from the strong covalent bonds between carbon atoms, making it the hardest known natural substance[4].

Rubies: The Fiery Red Gems

Known for their deep red hue, rubies are a variety of the mineral corundum. Their color is a result of the presence of trace amounts of chromium, which replaces aluminum atoms in the crystal lattice. The chromium ions absorb certain wavelengths of light, resulting in the red fluorescence when exposed to ultraviolet light[5]. Rubies are valued for their exceptional hardness, second only to diamonds, and their striking colour.

Sapphires: A Symphony of Blue

Like rubies, sapphires are also a variety of corundum. However, their stunning blue color comes from the presence of trace amounts of iron and titanium, which replace aluminum atoms in the crystal lattice[^6^]. These impurities cause the sapphire to absorb specific wavelengths of light, giving it its characteristic blue color. Sapphires are prized for their hardness and beautiful hues, which can range from deep blue to lighter shades.

The Art and Chemistry of Crown-making

Creating a royal crown is a delicate process that combines centuries-old craftsmanship with modern technology. The gold is first melted and poured into a mold to form the crown's base. Skilled artisans then carefully set the gemstones into the crown, ensuring that each stone is securely held in place.

References

[1]: Hammond, C. R. (2000). The Elements, in Handbook of Chemistry and Physics (81st ed.). CRC press.

[2]: Harlow, G. E. (1998). The nature of diamonds. Cambridge University Press.

[3]: Hughes, R. W. (1997). Ruby & Sapphire. RWH Publishing.

[4]: Nassau, K. (1981). The Physics and Chemistry of Color: The Fifteen Causes of Color. Wiley.'