Gemstones

Gemstones are nothing else than precious stones found all over the world, usually in crystal form, but with some exceptions. These stones are not rocks, therefore they are not usually quarried in big blocks which will be cut in a “slab” format as it commonly happens for Granite, Marble or Onyx, but they are mostly crystals of various sizes, depending on the stone. The only way some of these stones can be used as dimension stones is through the process which creates Semi-Precious Stone. Gemstones are often used as decoration, and they are said to have different metaphysical properties which can help your mood, health or energy. Following, a list of the most common Gemstones with a brief description.

.

.

.

.

.

.

Agate Agate is a translucent variety of microcrystalline Quartz, it is a banded variety with curved bands, opposite to the parallel bands of Onyx. This stone can be found in many different colours, such as red, pink, black, yellow and white, all caused by impurities. Agate is probably the most popular Gemstone seen around, it is used under the form of cabochons, beads, and very often sold as bookends, and it’s also one of the stones used to create Semi-Precious Stone slabs, taking their name from the included Agate’s colour. Because of the commonly unimpressive colours of Agate, most of the times this stone is dyed with tints of blue, purple, green and other hues to make it more attractive to the market.

.

.

.

Amazonite Amazonite is the trade name given to a particular feldspar of a light green, blue-green, bright green colour found near the Amazon river, where it takes its name from. its hardness on the Mohs scale is around 6, therefore it can be tumbled easier than other Gemstones

.

.

.

Amber Amber is a resin, secreted from ancient plants, which underwent a fossilization process. Its colour is characteristically orangish brown, but it can also be found in tones of white, blue or even black. It is generally cut, polished and used as a gem.

.

.

.

Amethyst This is one of the most popular Gemstones found around the globe. It’s a variety of Quartz, characterised by a purple colour. With a Mohs hardness of 7, it’s durable enough for nearly any use, and it’s relatively low-priced thanks to the huge deposits available in some areas of our planet. This stone is often sold in geodes and other natural occurring forms, but also many different crafts are made with it, such as coasters and crystals. Amethyst is associated with the Crown Chakra, a “spiritual centre” located on top of our head, which controls trust, devotion, inspiration, happiness and positivity.

.

.

.

Diamond Here it is, the toughest material on Earth, the only natural one which scores a solid 10 on the Mohs hardness scale. This is a rare occurring mineral solely composed by carbon atoms, held together by a strong covalent bond, the strongest of chemical bonds. It has  numberless properties, from high thermal conductivity, to high refraction index, and therefore is used in many fields, making it the most popular Gemstone.  Diamonds have a very bright luster, defined “adamantine” because of its unique brightness, and a high dispersion; that means it can separate lights into its component colours. The rarest, and most pricey, Diamonds are colourless, but they can also be found in shades of pink, yellow, red, blue, green or other hues.

.

.

.

Emerald Emerald is part of the beryl minerals’ family, a particular gem-quality specimen with characteristic green colour. Normally, a beryl mineral is colourless, but when it contains traces of chromium and vanadium, it develops the green colour typical of Emeralds, which can instead be defined “green beryl” if not saturated enough. Its Mohs hardness score is between 7.5 and 8, so high enough to make any use of it, but it has durability issues, in fact it contains few fractures which will ruin the stone over time, making it brittle and subject to break.

.

.

.

Jade Jade is a Gemstone commonly known for its characteristic green colour; although, it can occur in other hues, such as white, lavender, yellow, blue, red or others. It can be polished to a vitreous luster, and it has a rather good hardness, in fact it was used in the past to make axes, knives, scrapers and other sharp objects. It is nowadays used in the jewelry field under the form of cabochons, beads, pendants, rings, etc…  Many minerals have similar colour and characteristic as Jade, and it is very hard to distinguish one from the other.

.

.

.

Labradorite Labradorite is a feldspar mineral which is most often found in igneous rocks such as anorthosite, Gabbro and Basalt. This stone is characterised by a strong play of iridescent colours, with shades of blue, orange, yellow, red and green, peculiarity called “labradorescence“, from the name of this stone. Its Mohs hardness is around 6.5, and it can also be found in blocks, which are usually cut and commercialised under slab format. Labradorite takes its name from the location it has been first discovered in, a city called Labrador on the Isle of Paul in Canada, but it’s nowadays quarried mostly in Madagascar and Finland, where exceptional specimens can be found. Another variety of Labradorite sees the stone having blue labradorescence on a white and black background; this type of stone is called Rainbow Moonstone, or also Labradorite White.

.

.

.

Lapis Lazuli Lapis Lazuli is technically not a gemstone, but a metamorphic rock which takes its characteristic blue colour from the presence of lazurite, a silicate mineral from the sodalite family. Because of its beautiful colours and malleability, Lapis Lazuli has been used and sold as a Gemstone throughout time. This rock is formed  when Marble or Limestone undergoing a metamorphic process have portions replaced with the lazurite mineral, therefore any rock which contains at least 25% of blue lazurite can be defined Lapis Lazuli, but because of its origin, it could also contain calcite, pyrite, Sodalite, mica and dolomite. Because of its porosity, this rock is generally dyed and covered in wax before it’s being sold as Gemstone, to get rid of white areas and confer it a vitreous luster.

.

.

.

Mother of Pearl Mother of Pearl is the inner layer of a mollusc shell. Usually white, cream or grey in color, it’s characterised by an iridescent play of colour, which made it a really popular stone for jewellery. It’s composed of a form of calcium carbonate called aragonite (commonly found in Travertine and Limestone too), shaped in nanoscopic hexagons and arranged in a continuous parallel lamina. It is also found on the outer coating of Pearls and the inside of molluscs such as pearl oysters, freshwater pearl mussels, and, in a minor quantity, abalone. Very often, rectangles of this material are cut and glued together on a resin slab, forming the homonym Semi-Precious Stone.

.

.

.

Opal Opal is a silicon dioxide material with evident iridescent colours, known as “opalescence“. Most Opal will sparkle colours like orange, green, yellow, blue red or purple. This stone has translucent properties. It is widely used for earrings, pendants and rings, however it has a Mohs hardness of about 5.5, therefore it’s softer than most Gemstones. Many different types of Opal exist, depending on colour, amount and tones of opalescence and sometimes provenience, different names are attributed to them. Some Opal have unique characteristics, such as fluorescence or complete absence of colour and opalescence.

.

.

.

Pearl Pearl is technically not a stone, but organic material produced within the mantle of a shelled mollusc. It is composed of calcium carbonate in a microscopic crystalline form, deposited in concentric layers. Pearls occur spontaneously in the wild, but they are extremely rare, and for this reason most of the Pearls sold as Gemstone are farmed from pearl oysters or freshwater mussels. This “stones” have a characteristic iridescence, like the interior of the shells they are produced from, although not all mollusc can produce iridescent Pearls, and these ones are therefore valueless. Pearls can come in different shapes and sizes, but the most valuable are perfectly round.

.

.

.

Quartz Quartz is simply silicon dioxide (SiO2), formed by two parts of oxygen and one of silicon. It is the most occurring material on the planet, and because of its properties it’s one of the most useful too. Quartz scores a solid 7 on the Mohs hardness scale, and therefore it’s durable enough to be found in all types of rocks and to be used in many fields, first one being in production of Engineered Stone, thanks also to its high resistance to chemical substances. It is also used on the production of glass, or in electronic products thanks to its electrical properties.Being one of the most resistant natural minerals, its sand (naturally found or created by crushing minerals) has uses in the building industry, used as abrasive for Sandblasting processes and as foundry sand or for the creation of refractory bricks. Quartz crystals have the ability of vibrate at precise frequencies, hence why they are the most useful material for the creation of watches, televisions and radios. Many different types of quartz are nowadays sold as Gemstone, both for their physical and metaphysical properties, the most common being Rose Quartz and Amethyst, but also Agate.

.

.

.

Rose Quartz Rose Quartz is a particular specimen or Quartz which has a pink colour. It’s a very common and widely occurring mineral all around the world, taking its colour from the inclusion of the mineral dumortierite. Being a variety of Quartz, its Mohs hardness score is 7, therefore it is widely used in jewellery and also used as a decorative item, especially because of its metaphysical properties. In fact, Rose Quartz is believed to lower stress and tension in the heart, clearing out bad feeling such as jealousy, anger, resentment and others, allowing the healing of heart’s issues, and it’s also used to attract love. In many shops you can spot  lamps having Rose Quartz crystals as lampshade, creating a backlighting effect thanks to its translucent properties.

.

.

.

Ruby Ruby is a gem of the corundum family, an aluminium oxide mineral (Al2O3). Depending on the impurities contained in corundum, the stone can assume different colours, for example a red colour, and produce what we define a Ruby, or a blue colour, producing the gem we call Sapphire. So, in the case of Ruby, corundum is stained with the mineral chromium, which will vary its tone from pale pink to deep red ,depending on the amount contained in the stone. Being a corundum, Ruby is a very strong gem, with an astonishing Mohs hardness score of 9 it’s the third most resistant stone after Diamond and Moissanite. Ruby is a very popular gem used in jewellery, for pendants, watches, rings and more.

.

.

.

Sapphire Sapphire is the name attributed to the blue coloured specimen of corundum, an aluminium oxide mineral (Al2O3). The characteristic blue colour comes from the inclusion of iron and titanium in the corundum, which stain the mineral with a colour tone ranging from pale blue to dark blue. The word Sapphire is although used for stones with a colour ranging from violetish blue to greenish blue, with the middle range of a rich blue colour being the most desirable. Together with its red counterpart, Ruby, it’s one of the most commercialised Gemstones, with an impressive score of 9 on the Mohs hardness scale it’s an extremely durable stone, used mainly for jewellery.

.

.

.

Sodalite Sodalite is a rare feldspathoid with a characteristic royal blue colour with white veining. This stone occurs in igneous rocks which formed from magmas rich of sodium (hence why the name “Sodalite”), often lacking of quartz and feldspar. It doesn’t only occur in blue colour though, it can also be found in shades of yellow, grey, green or pink, but blue is the most popular and commercialised specimen. For this reason, it’s often confused with Lapis Lazuli, which is not a mineral, but a rock formed by several minerals, including Sodalite, and it also contains a considerable amount of pyrite, contrarily to Sodalite, which has none. Lapis Lazuli also has a higher value, hence why Sodalite is often called “poor man’s Lapis”. Its Mohs hardness score is between 5.5 and 6, limiting its uses to items which are not subject to scratching.

.

.

.

Topaz Topaz is a rare silicate mineral, widely sold as a Gemstone in a huge variety of colours. Although the name Topaz as always been associated to a yellow gem, most often it naturally occurs colourless or milky. Yellow and brown are popular colours too, and other colours such as purple, orange, red pink or blue are rare and very valuable. Most of the Topaz stones sold today at affordable prices are although treated with different techniques to change their natural color to more desirable ones, mainly blue and pink. The score for this stone on the Mohs hardness scale is very high, a solid 8, which is beaten only by Diamond and corundum (Ruby and Sapphire).