A replica of St Edward's Crown (1661)

On Saturday 6th May 2023 King Charles III will be crowned in Westminster Abbey. It is the first such coronation since his mother, Elizabeth II’s 70 years ago in 1953. The United Kingdom possesses the largest intact collection of royal regalia [1] in the world, and much of it will be used for Charles’ coronation.

Three crowns, an orb, a sceptre, and an 800-year-old spoon are among the items that will be used during the ceremony this weekend. The jewels are set with Rubies, Amethysts, Sapphires, several thousand diamonds.

Sapphire in process

Although we do not display them like the Crown Jewels, Specac is familiar with many of the materials used in royal regalia. Where royalty prize these materials for their rarity, clarity, and lustre, spectroscopists prize them for their optical transmission and physical robustness.

The Imperial State Crown which Charles will wear as he leaves the Abbey is adorned with St Edward’s Sapphire – a large oval shaped stone with the typical deep blue tone of polished Sapphires. As an optical material, Sapphire is hardwearing, suitable for prolonged immersion in liquid process streams. It transmits across the ultraviolet, visible, and near infrared ranges (0.17 to 5.5 μm [2]) and is the standard material for our Process Spectroscopy line-up.

Read more: Design considerations for liquid process streams.

Process flow cell with fibre optic connections for NIR process spectroscopy (process analytical technology)

Jubilant Diamonds

The Sovereign Sceptre with Cross is set with the largest colourless cut diamond in the world, cut from the Cullinan diamond discovered in South Africa in 1905. Diamond is valued by infrared spectroscopists as an excellent material for FTIR-ATR spectroscopy. It has a high refractive index and is extremely durable and resistant to chemical attack. It is the same refractive index of diamond and other precious stones which gives rise to their characteristic sparkle when used as jewels.

For FTIR-ATR spectroscopy, however, lab-grown synthetic diamond is quite adequate. Diamond is complemented by other materials that have different optical properties: germanium has an even higher refractive index, lending itself to analysis of shallower surface layers than diamond. Zinc selenide is another common material with similar optical properties to diamond, but less chemical resistance.

Read more: the versatility of the Quest ATR.

Close-up of the diamond ATR crystal set into the top-plate of the Golden Gate ATR unit

Gemstone Analysis

FTIR spectroscopy itself is a magnificent technique for determining the authenticity of gemstones. Although the authenticity of the Crown Jewels is not in doubt, the high value society placed on shiny, lustrous stones makes them a frequent target of fraudulent substitution with lesser materials. For instance, in 2001, huge quantities of a rare, pink-orange sapphire called padparadscha started to appear in the Asian gemstone markets. Scientists identified that the gems were, in fact, cheaper sapphires that had been treated with beryllium and then fraudulently sold as padparadscha. A scandal followed, and the sapphire market took a serious hit.[3]

Identifying synthetic, improved, and fraudulent gemstones can now be attained rapidly and easily using affordable equipment. Vibrational spectroscopy is becoming increasingly vital in the field of gemology. Reflectance infrared spectroscopy techniques, such as diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), are mainly useful for gemstone analysis as they are simple, rapid, and highly accurate and the equipment required is robust and low-cost.

Specac winners of royal award

Specac received the Queen’s Award for Enterprise in 2018 in recognition of its success in International Trade. The award lasts for five years and so, fittingly, the King’s coronation marks the final year of our award. Specac continues to have great success in its international business, supported by our great colleagues in the USA, Singapore, and China, as well as our network of distributors throughout the world.