Multicolour Gemstones

Multicolour Gemstones
By Alice Koh
[For educational purposes only].

Multicolour gemstones display multiple colours in a single stone. Ammolite, fluorite, andalusite and tourmaline are just few examples.


Ammolite is one of the rarest and one-of-a-kind gemstones in the world. It is an organic gemstone like pearls and amber. It is formed in a biological process instead of a mineral process like most gemstones. It comes from the fossilized remains of ancient shells of ancient sea creatures known as ammonites. Ammonites are a type of mollusk that went extinct at around the same time as the dinosaurs 65 million years ago. The shells of ammonites are made of aragonite, the same material found in nacre, abalone and pearls. It is extremely rare as it can only be found in Alberta, Canada.

Ammolite is iridescent which means that it exhibits a gorgeous display of colours.

Ammolite can display three to four colours such as red, green, blue and violet and these colours are visible from all angles.

Ammolite is protected by a hard backing of dark shale to make it harder and durable. Sometimes this ammonite doublet has a triplet protection by adding a transparent cover laid on top of the ammolite gemstone.

Ammolite has a hardness ranging from 3.5 to 4.5 on Mohs scale which without the doublet or triplet protection it would be too soft for use in jewellery.


Fluorite is known as the "most colourful mineral in the world."

It comes in brilliant colours such as blue, green, yellow, purple, pink, brown, orange, in one single stone. The rare colour-change fluorite comes in blue, purple and milti coloured.

Varieties of flourite that have particular colours or patterns include:
Blue John - (also known as Derbyshire Spar) is a semi-precious mineral, a rare form of fluorite with bands of a purple-blue or yellowish colour. It is found only in England.

Chlorophane - exhibits green thermoluminescence when heated.

Fluorite is not enhanced or treated in any way to enhance its beauty and colour.

Fluorite deposits are found in Brazil, India, France, Germany, Mexico, Morocco, Myanmar, Namibia, Russia and the United States.

Blue John is mined in limited quantities in Derbyshire, England but a similar fluorite gemstone has been discovered in China.

Fluorite had a hardness of 4 on the Mohs scale which makes it very soft for use in jewellery.


Andalusite is a clear and bright gemstone which changes in colours as it moves from one angle to another. It comes in shades of brown, yellow, orange, red and gold.

Andalusite is an aluminum silicate mineral named after the Spanish province of Andalusia. It is a polymorph with two other gemstones - kyanite and sillimanite. Polymorph means that they share the same chemical make-up and ingredients but have a different crystal structure.

Most Andalusite tend to be a greenish-brown colour but display flashes of orange, pink or red when turned from angle to angle

Andalusite is not known to be treated in any way to enhance its beauty and colour.

Andalusite can still be found in Spain, but also in Brazil, Sri Lanka, Australia, South Africa and the Inyo Mountains of California in the US.

Andalusite has a hardness of 7.5 on the Mohs scale which makes it durable enough to be used in all types of jewellery.


Tourmaline comes from the ancient Sinhalese (from Sri Lanka) "THORAMALLI" which means a mixed coloured stone.

Tourmaline is a complex crystalline boron silicate mineral which owes its variety of colours to the presence of additional minerals such as sodium, lithium, calcium, magnesium, manganese, iron, chromium, vanadium, fluorine and copper.

Tourmaline occurs in every colour of the rainbow in deep reds, pastel pinks, dark greens, vivid yellows and vibrant blues and also in combinations of 2 or 3 colours; rarely is it colorless. Though it can be found in a myriad of colours, it is more common in black to bluish-black. The blackish stone is called schorl and this variety accounts for 90% of tourmalines in nature.

Tourmaline has a hardness ranging from 7 to 7.5 on the Mohs scale. It is transparent to opaque with a glass-like luster. Cat's eye effect in tourmaline is very rare. If found, it usually only occurs in large crystals and they are most likely to be in green or pink and can exhibit strong pleochroism. Pleochroic means that it can change colours when viewed from different angles.

Tourmaline promotes healing and brings balance to the soul. It is often referred to as a stone of wisdom as it inspires positive attitude and stimulates creativity and learning.

Tourmalines is not known to be treated in any way.

Tourmaline is sourced from Brazil, Sri Lanka, Mozambique, Tanzania and Madagascar.

Tourmaline is the official birthstone of October. It is the traditional gemstone to celebrate the 8th wedding anniversary.


This rare beautiful stone changes colours before your eyes from reds, blues, purples, yellows and other colours. Few gemstones are as stunningly beautiful as labradorite.

Labradorite comes from Labrador, in Canada where the Inuit people believed that the Aurora Borealis was trapped within the Labradorite rocks and this transformed the stone into a rainbow-like magical dance of colourful lights.

Labradorite is like a prism. As light passes through its many thin aggregate layers of the stone, different wavelength of the light strikes a different layer and each layer reflects different colours of light. This unique dispersion of light creates the lovely dance of colours.

This play of colours is called the schiller effect, also known as labradorencence, aventurescence and adularescence. Opals and fire agates also have this schiller effect but they differ so much from labradorite that each of these stones can be catalogued very easily.

Labradorite comes in a variety of colours such as dark grey to grey-black, colourless, orange-red and brownish with colourful iridescence. It is often found in the deep blue range of colours.

Its hardness is 6 to 6.5 on the Mohs scale which means that it is hard enough for any type of jewellery.

Labradorite is of the magical feldspar family which also includes spectrolite, rainbow moonstone and moonstone.

Labradorites can display many colours you care to imagine but blue, green, yellow or red are most likely to appear. More rarely, purple, gold, teal and orange are also displayed. It is not treated in any way to enhance its beauty and colour.

Labradorite is mined in Canada as well as Madagascar, Russia, Australia and the United States while the fine spectrolite version comes from Finland.


Pietersite was named after Sid Pieters who discovered it in Namibia in 1962. Today "Pietersite" is a general term used to describe dark blue-grey breccia aggregate made up mainly of hawk’s eye and tiger’s eye.

Pietersite is a trigonal, fibrous aggregate crystal structure. It is a pseudomorph of quartz. It began as a crocidolite but over the years the crocidolite fibers are replaced by quartz. It is made up of both tiger's eye and hawk's eye breccia aggregate in its varying degrees of alteration.

Pietersite is easily identified by this unique chaotic cat's eye effect, caused by brecciated crocidolite inclusions. Depending on the density of crocidolite inclusions, pietersite can have the appearance either gray-blue, orange-brown or an equal mixture of the two.

Pietersite colours include blues, rusty reds, golds and browns. The blues range from light blue to a dark midnight blue colour.

Pietersite has a hardness ranging from 6.5 to 7 on the Mohs scale. This means that it is durable and resilient for everyday wear. It is opaque and displays a gorgeous silky luster. It has a moderate to strong green and white fluorescence.


Mystic Quartz is called thus because its gorgeous rainbow colours of green, blue and purple are something magical, mysterious, mystical and bewitching to behold. Mystic quartz is not gemstone per se but an enhanced colourless rock crystal.

Mystic quartz first made its appearance in the gemstone market in 1998. It is a natural colourless or white quartz also known as rock crystal that has been enhanced or coated to give it a unique rainbow colour effect. This enhancement is not permanent.

A clear thin coating is applied to colourless quartz resulting in an infinite combination of unique colours. Mystic quartz is very kaleidoscopic which makes the stone unique and fascinating.

Two of the most popular varieties of mystic quartz include the pink mystic quartz and the deep blue mystic quartz variety.

The magical colours in mystic quartz change as soon as you tilt the gemstone. What sets mystic quartz apart from other gemstones is that every single colour imaginable can be seen in this one quartz.

Mystic quartz has a hardness of 7 on the Mohs scale which makes it flexible and durable for any type of jewellery.

Rock crystal empowers and invigorates the wearer both in his or her self-confidence and self-love. It helps the wearer to rid of all forms of negativity and offers a powerful protection from harmful energy fields.


Agate gemstones have been used in jewellery since ancient times. It was considered a very spiritual gemstone used in seals and amulets.

Agate comes in colours such as blue, red, lilac, pink and yellow. They can be found in a variety of lovely patterns, stripes and bands.

Agate is of the banded chalcedony quartz species.

There are many varieties found in agate such as:

Blue Lace Agate


Moss Agate

Fire Agate

Agate is often not treated except green and yellow agates which are dyed to create a desired even colouring. This dye is safe and does not wash away or fade.

Agate like all quartzes, has a hardness of 7 on the Mohs scale which makes it suitable for all types of jewellery.

Agate is a mystical birthstone for September. It is also the gemstone gift for the 12th and 14th wedding anniversaries.


Fire agate comes with a gorgeous iridescence and round bulges often described as botryoidal which means it is shaped like a bunch of grapes.

Fire agate has a dark brown to black body upon which a rainbow of colours is exhibited. Colours such as red, gold, green and blue come out like a prism. Other colours include purple, orange and yellow.

Fire agate is a type of chalcedony which in turn is a kind of quartz.

Fire agate is not known to be treated or enhanced in any way. It is rare and can only be found in the south western parts of the United States and in northern Mexico.

Fire Agate has a hardness of 7 on the Mohs scale which makes it suitable for all types of jewellery.


Black opal is just one of the many varieties of opals. Other varieties of opals include white opals, boulder opals, fire opals, pink Peruvian opals, hyalite opals and many, many more.

Black opal is the most valuable and one of the most well known of the opal family. It comes with a dark background, displaying the play-of-colour phenomenon and its kaleidoscopic rainbow of colours.

Other famous opals include:

White Opals
Matrix Opals
Fire Opals
Hyalite Opals
Cat's Eye Opals
Boulder Opals

The red and orange colours in black opal is rarer and more expensive than blue or purple colours.

To darken the background of opal in order to bring out its colours, a couple of methods are used. One is to submerge the black opal in a solution of sugar and then acid. The other way is to smoke it.

Almost all black opals are mined in Lightning Ridge, in northern New South Wales in Australia, also in Ethiopia in North East Africa.

Black opal ranges from 5.5 to 6.5 on the Mohs hardness scale which makes it a bit fragile for rings and bracelets unless it is placed in protective settings.

Black opal is the birthstone of October. A black opal is the traditional gemstone gift for the 14th wedding anniversary.


Boulder opal is also one of the most famous of the opal gemstone family. It is called such because it is still attached to the host rock in which it is formed.

Every boulder opal is unique in both shape and colour. Boulder opal displays many different colours of the rainbow that dance before your eyes.

Two of the main colours in boulder opals are red and blue. Other colors include orange, green and purple.

Boulder opal is not treated in any way to enhance its beauty and colour.

All boulder opals come from central Queensland.

Boulder opal has a hardness ranging from 5.5 to 6.5 on the Mohs scale. This makes it a bit soft, but the attachment to the host rock makes it much more durable.

Boulder opals is the birthstone of October and the traditional gemstone gift for the 14th wedding anniversary.


Jasper means spotted stone. It is found in patches of colours, contrasting swirls and lines across the surface of the gemstone with light and dark patches in different colours.

Jasper comes in colours such as brown, red, honey, bright orange, yellow or a mixture of different colours.

Jasper is composed of iron that causes the earthy colours, manganese that brings in blue tints and clay that creates the yellow tone.

Jasper is a type of chalcedony which is a type of quartz. It is a microcrystalline quartz which means that the crystals are too small to be seen with the naked eye. It is opaque in its transparency.

Jasper is not known to be treated in any way.

Jasper is sourced from India, Australia, Venezuela, Russia, Brazil and Uruguay. Madagascar and the islands of Indonesia provide fantastic multicoloured jasper gemstones.

Jasper has a hardness of 7 on the Mohs scale which makes it suitable for all types of jewellery.

Jasper is a traditional birthstone for March.

Here are other multi-coloured gemstones not included in the photo:


Chrysocolla is of a greenish blue colour. However it can also be found with quartz, chalcedony, malachite, azurite and even opal which can create a whole rainbow of other colours as well as intriguing patches and patterns.

It is the mineral copper that creates the greenish blue colour in chrysocolla.

Chrysocolla began as a sort of gel that hardened over time composed of copper silicate. It is usually combined with other minerals such as turquoise, quartz, malachite and others which not only creates interesting patterns and colours but also makes it durable enough to be used as a gemstone.

Chrysocolla is not treated in any way to enhance its beauty and colour.

Chrysocolla is usually mined in Southern Israel but can also be found in Australia, Russia, the USA and Mexico in North America, Chile and Peru in South America.

Chrysocolla has a hardness ranging from 2 - 4 on the Mohs scale which makes it very soft for use in jewellery but the inclusion of quartz and chalcedony in its physical make-up usually strengthens this gemstone considerably.


Coral is an organic gemstone like ammolite. This means that it has a biological origin.

Other organic gemstones include:


Note, coral is not the same as fossil coral. Precious coral is derived from natural coral found in deep waters in tropical reefs. Fossil coral is the product of millions of years from the skeletons of natural coral replaced by agate. Thus it is more of a chalcedony variety than of precious coral.

Coral can be found in pink or red colours, with salmon or orange variations in some specimens. Some waters can create gold, white, blue or black coral but this is incredibly rare.

Coral colours can fade over time if exposed to heat or direct sunlight so it should be kept tucked away when not being worn.

Coral jewellery has been worn by humanity since ancient times. It was endowed with spiritual powers and often used as amulets to protect the wearer from evil.

Coral is not treated in any way to enhance its beauty and colour.

Precious coral is sourced from Italy, Australia, Egypt, Indonesia, Taiwan, Japan and Hawaii.

Precious Coral has the hardness ranging from 3 to 4 on the Mohs scale which makes it quite soft for use in jewellery. However necklaces, pendants, brooches and earrings will have no problem.


Fossil Coral is a one-of-a-kind gemstone in appearance and its creation. It took millions of years for a fossil coral to be created.

Fossil coral can be found in a range of colours, from white to brown, to reddish and pinkish colour.

Fossil coral is not an organic gemstone. Over millions of years the primary biological material was replaced by cryptocrystalline quartz commonly called agate. Thus, fossil coral is also called ‘Agatized Coral’.

Fossil coral is a quartz which was formed over millions of years while precious coral is a gemstone quality variety of natural coral.

Fossil coral is a mixture of coral and agate. Hence, it carries the metaphysical properties of both precious coral and agate. A grounding protective gemstone.

A small flower-like shape decorates the surface of the better examples. Attractive patterns of bright yellow, red or orange colours are most valued.

Fossil coral is not known to be treated in any way to enhance its beauty and colour.

Fossil coral has been used as amulets since ancient times. It is found on beaches or climbing cliffs in the United States and Indonesia. The state of Florida in the United States has declared fossil coral its official 'Florida State Rock'. Indonesian fossilized coral is considered to be the most desirable and unique.

Fossil coral has a hardness ranging from 6.5 to 7 on Mohs scale which is harder than precious coral and thus suitable for all types of jewellery.