Gemstone Guide


At Amadeus, we only work with ethical gemstone sources who are part of organisations such as AGTA (American Gem Trade Association) in the US and in Europe the WFBD (World Federation Diamond Bourse) who set the highest ethical standards for its members. We also try to recycle as many gemstones as we can from vintage jewellery pieces. In keeping with our own ethos, we only align with sources who have integrity and passion for their business.


Amazonite is the green to turquoise form of the mineral microcline although very keen sellers of this gem may include off-white or gray stones with a hint of green as amazonite. It is not an official birthstone or a wedding anniversary gemstone however it is treasured as a birthstone for those born under the Virgo astrological sign.


Amethyst is a quartz gemstone found in shades of purple, ranging from intense violet purple, to subtle pink-lilac. It can also be found in shades of green and rose pink, though harder to find. Amethyst is the birthstone for February.


Citrine is a quartz gemstone found in shades of lemon, yellow, orange and sherry colours, sometimes referred to as lemon quartz. Most Citrine is from Brazil. Citrine is the birthstone for November.


Garnet is a family of gemstones coming in a spectacular array of rich colours. Ranging from semi-precious to precious, red garnet is the most common. Almandine garnet is much more rare and is prized for its lustrous colour. Rhodolite garnet is very similar to Almandine. Garnet is the birthstone for January.


Labradorite is a feldspar gemstone, meaning a stone that is found scattered not far beneath the earth’s surface. The distinctive iridescence and flashes of metallic blues, greens, golds and bronzes are created by light interplaying with the internal structures within the stone. It is named after the Labrador Peninsula in Canada where it is found, but also occurs in Russia, Norway, Finland and India.


Lapis Lazuli, the finest gem quality stones are intense blue sometimes with a dusting of golden pyrite and are highly prized, though can be found in great abundance. Sources include Afghanistan, Russia, Chile, the USA and Canada.


Moonstone is an opalescent gemstone found in shades of white, green, grey or rainbow - which as it suggests, reflects all different colours. It is a feldspar meaning it is formed in rocks near the Earth’s surface. The most important sources are found in Burma, Sri Lanka and India. Moonstone, along with pearls, are the birthstone for June.


Peridot is a distinctive apple green colour varying in intensity. It is part of the olivene family. It is unusual in that small stones are relatively inexpensive, but larger stones of intense colour and good clarity are of gem quality. Deposits are found in China, Burma, Australia and South Africa. Peridot is the birthstone for August.


Prasiolite is a rare form of green toned Quartz, a silicon dioxide mineral that contains Iron. It is found naturally in Brazil, Thunder Bay Canada and Poland. The green colour, often referred to as ‘leek green’, ranges from a light green/yellow, green/gold to greenish/ grey and is mainly translucent. 


Rock Crystal, a transparent, colourless quartz, found in Brazil, Madagascar and the USA. The Greek word for rock crystal was krustallos, meaning ice, because it was believed quartz was ice formed by the gods - see quartz. Along with diamonds, rock crystal is the birthstone for April.


Smoky quartz is sourced in shades of brown from subtle to rich brown to almost black. Quartz is a crystalline rock composed of silicon dioxide. Semi-precious gemstones belonging to this group include citrine, amethyst, green amethyst, smoky quartz, lemon quartz, lime quartz, rock crystal, rutilated quartz and tourmalinated quartz. The vast range of colours are created by the presence of different minerals. Our quartz gemstones are mostly sourced from Brazil and India.


Tourmaline has perhaps the largest range of colours available including green, blue, turquoise, red, pink, purple, yellow and brown. Most varieties are simply called tourmaline, however, some of very special quality have their own name – pink-red is referred to as rubellite, deep blue tourmaline is called indigolite and a rare turquoise green is known as paraiba. They are found in India, South America, Africa, Russia and many other parts of the world.


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