What is a gemstone? It is usually defined as being a mineral that exhibits beauty, durability and rarity. Also considered to be gemstones, though, are some rocks like lapis lazuli and some organic pieces such as pearls, amber, jet, tortoiseshell and ivory. Gemstones have been used in jewellery for centuries but many were only discovered in the last few centuries. Amazingly, we are still finding new gemstones. There are around 300 varieties of gemstones but only about 130 are used for jewellery. Some gemstones epitomise an era and then fall out of favour while others have remained eternally popular. Discoveries such as the gemstones in Brazil by the Portuguese in the 1700s in particular led to an influx of colourful gemstones for use in jewellery. Some gemstones were not properly identified until the 17th, 18th and 19th centuries, as scientific methods developed.
So which stones were used in ancient times, found in jewellery excavated from burial sites or represented in paintings over the centuries?
They were amber, aquamarines, emeralds, cat’s eye chrysoberyl, rubies, sapphires, star sapphires, diamonds, garnets, iolite, jadeite jade and nephrite jade, jet, malachite, opal, pearls, peridot, amethyst, carnelian, citrine, rock crystal, rose quartz, smokey quartz, spinel, topaz, tourmaline, turquoise and zircons.
Which stones were confused with other stones?
All yellow stones were once thought to be topaz. Citrine in particular was sold as topaz. It was also not recognised that topaz came in many colours – pink, blue, colourless, brown, green, orange, and violet – until 1737. Pink topaz became popular in the 19th century after the discovery of large deposits in Brazil and a pinkish orange topaz mined in Russia was so prized by the Czar, its use was restricted to the royal family. Most pink topaz will have been heat treated as pink is a rare colour to occur naturally. Blue topaz became common in the 1960s due to better methods of irradiating colourless topaz to produce blue. Colourless topaz stones were often used as imitation diamonds before the creation of stones like cubic zirconia, moisonnite and synthetic diamonds.
Spinel and rubies are really the only true red gemstones mined and were often mistaken for each other. Part of the reason for this is that, apart from the colour, they are often located together in the ground. Spinel occurs in lots of different colours – blue, flame orange, violet, purple, pale pink, black and blue green – but historically, it was the red spinel that was used. Famous spinels are found in the Russian Imperial Crown commissioned by Catherine the Great for her coronation in 1762 (approx. 400 carats); the ‘Timur Ruby’ (352.5ct) found in the Crown jewel collection of the British monarchy and thought to date back to 1300, and the Black Prince ‘ruby’ (approx. 170 ct) given to Edward, son of King Edward III, in 1397, and later set in the Imperial State Crown. The ‘Timur Ruby’ and the ‘Black Prince Ruby’ were identified as spinels around 1852.
Some dates about other gemstones – chrysoberyl were found in the late 1600s in Sri Lanka, then deposits were found in Brazil in 1805; aquamarines were discovered in Russia in 1723; spodumene was not identified until 1879 in North Carolina; alexandrite from the chrysoberyl family was first discovered in Russia in 1830 and then a new deposit in Brazil in 1975; and black precious opal was discovered in Australia in 1872.