A gemstone is a mineral crystal that can be found beneath the surface of the earth. It is extracted, cut and polished, and used to make jewellery among other things.
Over the years, an endless array of stones have been discovered and studied by gemologist’s world over. So the classification of gemstones can be distributed based on the hardness, colour and various other properties so that buyers can distinguish them and assert their value and rarity.
Types of Gemstones
Gemstones are mainly divided into two categories: 1.Precious and 2.Semi-Precious
- Diamond is the most famous gemstone.
- The hardness of the diamond makes it useful not just for jewellery but also for industrial usage. However, diamonds have been used as jewellery pieces and ornamental items since ancient times and is now mainly used to symbolize love with an engagement ring.
- If you wish to learn some more interesting facts about diamonds you can check out our previous post.
- The famous blood-red gemstone, the colour due to the element chromium.
- It is one of the traditional cardinal gems and is a variety of the mineral corundum. Like all other gems, the value and quality are determined by its four C’s.
- The brightest and most valuable shade of red called blood-red or pigeon blood commands a large premium over other rubies of similar quality.
- The ruby with the brightest and most valuable shade of red is called blood-red or pigeon blood, hence it is no surprise that the titles of the most expensive ruby, the most expensive coloured gemstone and the most expensive gemstone, besides the diamond is the Sunrise Ruby. Learn more fun facts about the ruby by clicking on this link
- Emerald is a medium to dark green beryl colored by chromium and in some cases vanadium.
- Since it is a variety of beryl, which has a hardness of 7.5-8 on the Mohs scale, unlike diamonds, most emeralds are highly included, so their toughness is generally poor.
- Sapphire is usually blue, but natural "fancy" sapphires are also available in yellow, purple, orange, and green colours.
- It a variety of the mineral corundum, consisting of aluminium oxide with trace amounts of elements such as iron, titanium, chromium, copper, or magnesium.
- Sapphires have a unique hardness, registers 9 on the Mohs scale. Besides being used famously in jewellery, they are one of the few precious stones widely used in electronics such as wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of very special-purpose solid-state electronics.
While there are many more Semi-Precious Stones in existence, the most prominent and popular are listed below..
- Garnet, being a popular semi-precious stone, are registered 6.5 to 7.5 on the Mohs scale, and are often confused for Rubies.
- The redness is caused by the presence of iron 2+ ions.
- The garnet is further classified into different species, and so the atomic bonds in some garnets are stronger than others.
- The harder species like almandine are often used for abrasive purposes.
- The traditional birthstone for February, this semi-precious stone displays a brilliant purple hue due to irradiation, impurities of iron and in some cases other transition metals.
- It is a variety of quartz and therefore shares the same hardness making it appropriate for use in jewellery.
- Citrine is often confused with topaz, the same way that ruby is confused with a garnet. However, unlike a ruby, citrine is categorized as semi-precious.
- Real Citrine is rare and like any other gem, can be imitated, and so most citrine is the result of heat treatment of amethyst. Iron present in citrine’s structure is credited for its brilliant yellow hue.
- It registers at 7 on the Mohs scale.
- Jade can be classified into two categories, Jadeite Jade and Nephrite Jade. Jadeite Jade is harder and more valuable than Nephrite, and is considered to be a precious stone. It is 6.5 to 7.0 hardness depending on the composition, and nephrite is 5.5-6.
- Most jade is available in a bright green colour and places alongside Emerald on the same colour spectrum. However Jade is available is also available in Dark lavender, red and yellow which is considered to be the most affordable Jade stone.
- Rare imperial green Jade, a translucent stone, is the most expensive in the world worth more per gram than diamonds.
- Jade jewellery, is believed to provide protection from evil and bring good luck, and so is worn by many people.
Precious and Semi-Precious Stones are further divided into Organic and Counterfeit gemstones..
A common feature of women’s necklaces and bridal gowns, pearls are considered to be precious stones. They fall under the organic category since they are produced by sea creatures in nature. It is composed of calcium carbonate in minute crystalline form, deposited in concentric layers. The most sought after pearl is round and smooth, and the best quality are valued as gemstones. Its hardness is 2.5 to 4.5 on the Mohs scale.
- Amber is fossilized tree resin. Not to be confused with tree sap. High temperature and pressure harden the resin into copal, which ultimately turns to amber because of the continued heat and pressure.
- Though not mineralized, it is classified as a gemstone and good quality amber is often used in jewellery.
- It has a hardness between 2.0 and 2.5 on the Mohs scale and a melting point of 250–300°C. Because its initial state was fluid, and it originates on the bark of trees, it tends to trap animal or plant material.
- A famous reference to this is the 1993 blockbuster, “Jurassic Park”, in which park owner and industrialist John Hammond, carries around a cane, with an amber head, entrapping a mosquito said to be from a dinosaur specific period.
- Corals are marine invertebrates that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. They are living creatures that depend on small fish or photosynthetic unicellular dinoflagellates for their energy and nutrients.
- Coral’s famous rainbow colours in the past were considered ideal for jewellery and for gifts. Red coral is considered as a gemstone.
- However, usage of coral in gifts and jewellery has been widely discouraged due to overharvesting, climate change and pollution which has led to the widespread decline in the coral reefs.
As the name suggests, counterfeit gemstones are manufactured artificially in high-end laboratories, to replace the more expensive naturally occurring gemstones.
And of course, the most widely counterfeited stones are Diamonds, Rubies, Emeralds, and sapphires, more than any other gemstone. These stones are made in the laboratory by mimicking the chemical elements of the natural stones.
To a true gemologist, a counterfeit can be spotted from a mile away, with a different and dull colour, and presence of air bubbles which cause a cloudy appearance among other things.
If you are serious about gemstones, you do not want to end up with an accidental counterfeit. So head over to our website, and we can guide you on how to pick up the perfect gemstone!