Gemstones

Beautiful creations of nature, gemstones come in a wonderful array of colours, sizes and shapes. A gem is a mineral or an organic material which is rare, valuable, durable and but also beautiful. If you are considering precious stones for your piece, then this guide should give you an inside about the fascinating world of gemstones. 

Availability & Rarity

Please remember that coloured gems are natural materials and their availability depends on what nature creates. Factors such as political instability or a mine being exhausted can also affect the availability of a gemstone.

Each stone is unique and not two gems are the same and sometimes finding two matching gemstones for a pair of earrings or several for a ring can be challenging.

Some stones are rarer than others, a gemstone can be rare for diverse reasons – its colour, its origin, its size or the type of mineral or material.

Durability

The durability of a gemstone is its ability to withstand wear, heat, light, household chemicals, and low or high humidity. So, knowing how durable a particular gemstone is will help you determine how and when to wear it.

The Mohs scale, ranks gem and mineral hardness on a scale of 1 (least hard – talc) to 10 (hardest of all – diamond). But hardness is not the only factor in determining gem durability.

Durability = hardness + toughness + stability
Hardness = resistance to scratches and abrasions
Toughness = resistance to breaking and chipping
Stability = resistance to chemicals, heat, humidity and light

You should weigh all three of these factors when deciding which gemstone to choose for your piece of jewellery.

For example, when choosing a gem for an engagement ring, make sure you pick a durable stone, suitable for everyday wear, such as a ruby or a sapphire.

Cut

The lapidary (person who cuts and polishes gems) will decide on the best cut to show off a stone’s feature, taking into account its colour, clarity and weight. The style of cut will also depend on the type of gemstone. Opaque and translucent stones will often be cut with a flat base and a domed surface, called Cabochon cut. But most gemstones are cut and polished into facets, so that the light can travel through the stone and making it sparkle. The number and shape of the facets gives the stone its style of cut. 

Gemstones

Precious gemstone:

• Mohs Hardness: 9

Deep blue sapphires called “royal blue” have long been associated with royalty and were often worn by medieval kings.

But sapphires come in almost every colour of the rainbow; pink, yellow, green, blue, orange and purple. Red sapphires are actually called rubies, both are varieties of the mineral corundum, one of the most durable naturally occurring elements in the world. The only natural item that can scratch a sapphire is a diamond, which has a 10 on the Mohs Scale. Sapphires are often heat-treated to improve their colour.

The durability and the colour range of sapphires, makes them the ideal choice for engagement rings.

For more info see 10 fascinating facts about sapphires

Ruby

• Mohs Hardness: 9

Latin for “red”, ruby is considered one of the four precious stones alongside sapphire, emerald and diamond. In ancient Sanskrit, ruby was called ratnaraj, or “king of precious stones.”

Ruby is the rarest and most valuable coloured gemstone and variety of the corundum mineral species, which also includes sapphire. It is traces of chromium that give this red variety of the mineral corundum its rich colour. It ranges from purple–red to blood red.

Just like sapphires, rubies are extremely hard stones and are an excellent choice for engagement rings and other every day wear jewels. 

Emerald

• Mohs Hardness: 7.5 to 8

Egypt was the earliest known location for emerald mining. Symbol of fertility and immortality “The Jewel of Kings”, was considered sacred by the ancients. Cleopatra herself was known to have a real passion for emerald and was renowned for having fabulous collection.

Part of the Beryl family of minerals this beautiful stone is famous for its recognisable vivid green colour. Internal inclusions are common within emeralds, making this stone less durable and more prone to chipping or breaking than other precious stones such as sapphire and ruby.

Because it requires a bit more care and attention, this beautiful green stone is an ideal choice for earrings and necklaces.

Semi-precious gemstones:

Amethyst

• Mohs Hardness: 7

From the Greek word amethystos “not drunk”, amethyst was believed to prevent intoxication. The ancient Greeks carved drinking vessel from amethyst and wore them as a guard against inebriation. It was once considered equal in value to ruby, emerald, and sapphire and has been set in religious jewellery and royal crown jewels for ages.

Ranging from a light lilac to intense rich purple, amethyst is a variety of quartz. A deep uniform purple colour is more valuable than the pale lavenders.

Beautiful, yet affordable amethyst is suitable for most type of jewellery.

 

 Aquamarine

• Mohs Hardness: 7.5 - 8

Latin for “seawater”, aquamarine’s fresh watery hue conjures up images of a clear, calm and tranquil sea. It was said to calm waves and keep sailors safe at sea.

Aquamarine is found in sea green, sky blue and dark blue colour. Today, the most valued colours are sky blue and dark blue, but in the past, sea green stones were preferred.
Part of the beryl family (same as emerald) aquamarine rarely features internal inclusions meaning it is exceptionally transparent and it is easy to find good quality stone at good size.

Fewer inclusions and cracks mean the material is less brittle making it durable enough for everyday wear.

 

 Garnet

• Mohs Hardness: 6.5 – 7.5

The name garnet comes from the medieval Latin “granatus,” meaning pomegranate, in reference to the similarity in colour.

But garnet is the name given to a group of mineral species, there are many types of garnets and they come in almost every colour: greens, oranges, pinkish oranges, deeply saturated purplish reds, and even some blues. Red garnet is one of the most common, but not all garnets are as abundant as the red ones. The green garnet, tsavorite, it’s rarer because it needs unusual rock chemistries and special conditions to form. Demantoid is a rare and famous green garnet, spessartine (also called spessartite) is an orange garnet, and rhodolite is a beautiful purple-red garnet.

Garnet is a hard wearing and durable gemstone, suitable for most types of jewellery.

 

Opal

• Mohs Hardness: 5 - 6.5

This fascinating stone has been credited with supernatural powers and origins by many cultures. There are so many legends and superstitions about this gem. The ancient Greeks believed opals guarded them from disease and gave their wearers the gift of prophecy. In ancient Rome, it was considered the most precious and powerful of all. The Bedouins believed that opals contained lightning and fell from the sky during thunderstorms. In the Middle Ages, opal was considered a stone that could provide great luck because it was believed to possess all the virtues of each gemstone whose colour was represented in the colour spectrum of the opal.

Opal is known for its unique display of flashing rainbow colours called play-of-colour. There are two broad classes of opal: precious and common. Precious opal displays play-of-colour, common opal does not. Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque and the background colour may be white, black, or nearly any colour of the visual spectrum. Black opal is considered to be the rarest, whereas white, grey, and green are the most common.

Opal is not the most durable stone and it is easily damaged, but it is impossible not to be seduced by its fantastic variety of patterns and colours. Because it is a soft stone, opal is an ideal choice for earrings and necklaces. Opal is sensitive to heat and chemicals; therefore, it requires extra care.

Pearl

• Mohs Hardness: 2.5 – 4

Natural pearls were the first gems coveted by prehistoric people. Found by chance while opening shells for food they were enchanted by the luminous glow emanating from these gifts of the sea.

Natural pearls occur spontaneously in the wild, but are extremely rare and the most valuable. Wild pearls form around a microscopic irritant in the bodies of certain molluscs.

Unlike natural pearls, the growth of cultured pearls requires human intervention and care. Cultured pearls are the result of the deliberate insertion of a bead or piece of tissue that the mollusc coats with nacre. Cultured pearls can be divided into two broad categories: pearls grown in salt water and pearls grown in fresh water. While both are beautiful, pearls grown in salt water are considered to be more valuable.

The most familiar colours are white and cream (light yellowish brown). Black, grey, and silver are also relatively common, but the palette of pearl colours extends to every hue. The bodycolor is often modified by additional colours called overtones, which are typically pink, green, purple, or blue.

Pearls being very soft they are best for bead necklaces or mounted in earrings, pendants or jewellery designed to protect the stone. Pearls are organic material and are sensitive to heat and chemicals and therefore require special care.

Read our full pearl guide for more info.

Peridot

• Mohs Hardness: 6.5 - 7

Peridot has been mined for over 3,500 years. Ancient Egyptians believed that peridot was sent to Earth by the explosion of a star and the gem has been associated with light. Peridot is the national gem of Egypt known to locals as the “gem of the sun”.

A good-quality peridot is very rare. Most peridots formed deep inside the earth and were brought to the surface by volcanoes. Very rarely, peridot can also have an extra-terrestrial source, being contained in meteorites that have fallen to earth. The green shades of the peridot are ranging from brown-green colour to yellowish green to intense green.

This beautiful green stone is an ideal choice for earrings and necklaces rather than rings because peridot will pick up scratches relatively easy

Tanzanite

• Mohs Hardness: 6 – 7

Tanzanite was discovered in Tanzania (hence the name) in 1967, by a Masai tribesman. This exotic rich blue stone is found in only one place on earth, near Mount Kilimanjaro.

It is a valuable, transparent stone, a type of zoisite-resembling sapphire. Tanzanite is blue, purple or violet depending on the angle at which they are viewed. Vivid strongly-coloured Tanzanite is highly sought after and more valuable than lighter tones of pastel hues.

Tanzanite is a special care gem due to sensitivity to thermal shock and the potential for cleavage. For everyday wear, it is best to choose jewellery that is designed to protect the stone, such as earrings, necklaces or pendants.

Topaz

• Mohs Hardness: 8

The ancient Greeks believed that topaz gave them strength, while Romans believed that the gem provided protection from danger while traveling.

Colourless topaz is plentiful, and is often heat treated or irradiated to give it a blue colour. But a natural topaz, is much rarer, more expensive than people might think. Topaz has an exceptionally wide colour range that includes various tones and saturations of blue, green, yellow, orange, brown, red, pink, and purple. The most expensive and desirable colours are yellowish brown or brownish yellow to orange (called sherry topaz), medium reddish orange to orange-red (imperial topaz) and pink.

Topaz is a hard stone, but can develop cleavage, therefore it is best set-in jewellery that is designed to protect the stone, such as earrings, necklaces or pendants.

Tourmaline

• Mohs Hardness: 7 – 7.5

Explorers discovered green tourmaline in Brazil in the mid 1500’s but confused the vibrant gem with emerald. Confusion lived on until scientists recognised tourmaline as a distinct mineral species in the 1800s.

Tourmaline has the greatest colour range of any gemstone species, occurring in various shades of every hue. Sometimes, tourmaline can have several colours in just one stone (bi and tri-colour). The best-known combination is the watermelon tourmaline in which the crystal has a green rim and a pink centre. Paraíba tourmalines are among the world’s most prized gemstones. These rare gems are renowned for showing intense blue colours.

Tourmaline is not the hardest stone; therefore, it should be worn with care if worn in a ring.

Our gemstones

We offer a stone sourcing service for all clients commissioning a bespoke piece from us. See our bespoke page for more info.

Over the years we have built a network of trusted U.K based gemstones suppliers who can guarantee all gemstones are from carefully selected and fully traceable sources around the world.

Most of our suppliers are working directly with artisanal and small-scale mines and stone cutters, to bring you high quality ethical gemstones and guarantee safe working conditions and fair pay for the miners as well as to ensure minimum disruption to our environment.

History & lore

Through the ages, various civilisations have set gemstones in jewellery and personal adornment; they have also been recognised by the ancients for their sacred, magical and healing properties. Found in Egyptian tombs and temples, the ancient Egyptians wore them as amulets and charms. Native Americans, Mayans and Aztecs all used gems for ceremonial purposes. In the Middle-Ages, gemstones were crushed into wine and administered as medicine.

Birthstones & anniversary

Some cultures associate gemstones with zodiac signs, whilst others have been associated with different months of the year. The custom of wearing birthstones has spread throughout the world, but can be sourced back to Poland in the 18th century.

With roots tracing it as far back as Ancient Rome, the concept of a theme gift for each anniversary is nothing new. Often the gift consists of a specific gemstone or metal.

For gemstone care and cleaning tips see jewellery care.