Carnelian
Colour: brownish-red, orange, pale yellow
Hardness: 6.5-7
Cleavage: none
Fracture: uneven, conchoidal
Crystal system: cryptocrystalline
Chemical composition: silicon dioxide, colouring agent - iron
Transparency: translucent to opaque
Carnelian – used in ornamental objects and jewelry throughout ancient Egypt, Persia, and Sumeria as early as 3000 BC. Also known as ‘sard’ this is probably named after one of the places that it was found, near the ancient Roman city Sardius, now in Turkey. During Roman times, Carnelian was a popular stone for use in cameos, intaglios, and signet rings
Found in Brazil, Australia, Madagascar, Russia, South Africa, USA, Uruguay and India. Carnelian is often heat treated to enhance the colour. It can be confused with jasper and agates.
Chalcedony
Colour: bluish, white, gray
Hardness: 6.5-7
Cleavage: none
Fracture: uneven, conchoidal
Crystal system: cryptocrystalline
Chemical composition: silicon dioxide, colouring agent - iron
Transparency: translucent to opaque
Chalcedony refers to all cryptocrystalline quartzes as well as specifically to the bluish variety. Probably named after an ancient town located at the Bosporous. A porous stone it can easily be dyed. The bluish variety is found in Brazil, India, Madagascar, Namibia, Zimbabwe, Sri Lanka, Uruguay and USA. Can be confused with tanzanite.
Metaphysical – a nuturing and creative stone. Helps open the mind to assimilate new ideas and accept new conditions. Traditionally used in weather magic and for clearing illnesses associated with the weather.
Charoite
Colour: lilac to voilet
Hardness: 5-6
Cleavage: good
Crystal system: monoclinic but found in massive form.
Chemical composition:
Transparency: transluscent to opaque
Named for the for the Chara River in which locality it is found, charoite was recognized as a mineral in 1978. A rare mineral it is only found in the Murun mountains in Russia. It has a fribrous look with swirling patterns and sometimes displays chatoyancy. Stones often include a mixture of black augite, clear microcline feldspar and orange tinaksite, yellow to brown batisite or ekanite, colourless to off white dellaite, green diopside, pink, lavender or red-brown miserite and quartz can create interesting patterns and effects.
Metaphysically considered a stone of transformation it overcomes fear, aids insight and change. It is believed to reduce stress and worry, compulsions and obsessions. In healing it is used to re-energise and treast the eyes, heart, liver and pancreas. It also helps restorative sleep.
Chrysocolla
 
Colour: green, blue
Hardness: 2-4
Cleavage: none
Fracture: conchoidal
Crystal system: monoclinic but found in massive/botryoidal forms
Chemical composition: hydrous copper silicate
Transparency: opaque
Some copper deposits began their lives as volcanoes - hot fluid circulate from magmatic cores in large underground loops through rocks as they returned to the volcanoes, taking with them trace elements, notably copper. It precipitated in cavities as elements and oxides, the water picked up and deposited carbonates and then picked up aluminium and silicon from the much-corroded lavas, ashes and rocks, depositing copper rich clays and low temperature minerals. One low temperature mineral was chrysocolla and another was quartz. 'Gem chrysocolla' is a combination of fine grained quartz and light blue chrysocolla - a material durable for jewellery.
A form of chrysocolla, intergrown with both malachite and turquoise is called “Eilat Stone” and was believed to have come from King Solomon’s mines.
Found in Chile, Isreael, Mexico, Peru, Russia, Ziare and the USA. Can be confused with azurite, malachite, turquoise and variscite.
Chrysoprase
 
Colour: apple green
Hardness: 6.5-7
Cleavage: none
Fracture: rough, brittle
Crystal system: cryptocrystalline
Chemical composition: silicon dioxide, colouring agent - nickel
Transparency: translucent to opaque
Chrysoprase – the name means ‘gold-leek’ in Greek and this stones is the most valuable of the chalcedonies. It was used by ancient peoples in jewellery and other ornamental decorations. In Europe pre-1300s, chrysoprase was mined in Poland and used for interior decoration in important buildings.
It is now found in Australia, Brazil, India, Kazakhstan, Madagascar, Russia, Zimbabwe, South Africa, Tanzania and USA. Can be confused with jade, prehnite, variscite and artificially coloured chalcedony.
Metaphysical - said by the ancients to promote a love a truth, it also promotes hope and gives personal insights. Drawing out talent it stimulates creativity and encourages fidelity. It encourages fluent speech, prevents nightmares and brings a sense of security. In healing it is believed to aid peaceful sleep, aids gout, eye problems and skin diseases.
Citrine
Colour: light to dark yellow, golden-brown.
Hardness: 7
Cleavage: none
Fracture: brittle, conchoidal
Crystal system: trigonal
Chemical composition: silicon dioxide
Transparency: transparent
Citrine – the name is taken from its lemon yellow colour (from the French word ‘citron’). Citrine was used by Greek civilization as early as the 4th century BC.
Natural citrines are not common and most citrine is heat treated amethyst or smoky quartz. The heat treated stones often have a reddish tint. Naturally coloured stones are found in Brazil, Madagascar, USA, Argentina, Burma, Namibia, Russia, Sctoland and Spain. Citrine can be confused with beryl, topaz and tourmaline. Synthetic citrine is available.
Metaphysical – carrying the power of the sun, citrine is classed as a beneficial, warming, energizing and creative stone. It absorbs and dissipates negative energy. A stone of abundance it attracts wealth, prosperity and success. It encourages sharing yet helps you to hold on to your wealth. It raises self esteem and self confidence and enhances self expression. In healing it is believed that it will stimulate digestion, increase blood ciculrtion and fortify the nerves.
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Coral
  
Colour: red, pink, white, black, blue
Hardness: 3-4
Cleavage:none
Fracture: irregular, splintery, brittle
Crystal system: organic
Chemical composition: calcium carbonate or conchiolin
Transparency: translucent to opaque
The name coral comes from the Greek and is a skeletal structure built by coral polyps. Found off the coasts in the Mediterranean, Red Sea, Bay of Biscay, off the Canary Islands, Malaysian archipelago, Midway Islands, Japan and Hawaii, Australia and the West Indies. The historical trade centre for coral is Torre del Greco in Italy and a proportion of coral is still processes there. Some traditional corals used in jewellery are endangered but other varieties - eg. sponge and bamboo coral are abundant. The colour can be enhanced and some colours will fade over time.
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Diamond
Colour: clear, yellow, brown, occasionally green, blue, reddish, orange, black
Hardness: 10
Cleavage: perfect
Fracture: conchoidal to splintery
Crystal system: cubic
Chemical composition: carbon – crystallized
Transparency: transparent to opaque
Diamond - from the Greek adamas (unconquerable). Considered the pinnacle of gemstones, it has been used in adornments since ancient times.
Formed under high pressure and heat at up to 450km below the earth’s surface they would come to the in volcanic eruptions and were found, prior to 1871, in alluvial deposits. After this date pipes of diamond bearing rock (kimberlite) were discovered in South Africa allowing further discoveries of similar rock in various locations around the world. Found in Borneo, India, Brazil, South Africa, Namibia, Australia, Botswana, Russia, South Africa, Zaire, Ghana, Angola and the Central African Republic.
Diamond can look similar to natural stones of rock crystal quartz, beryl, cerussite, sapphire, sheelite, sphalerite, topaz and zircon. Naturally there are also imitations and synthetic (manmade) stones eg. cubic zirconia.
Some famous diamonds
The Hope diamond – a bright blue diamond of 45.52 carats surfaced in 1830. It is believed to have been cut from a stolen stone.
The Cullinan I or Star of Africa – a whopping 530.20 carats, this pear shaped colourless diamond in on the scepter of the English monarch and is kept in the Tower of London with the other royal jewels.
The Koh-i-noor – an oval stone of 108.92carats it was originally a round stone of 186 carats. First reported in 1304 as in the possession of the Raja of Malwa. It later fell into the hands of the Baber who founded the Mogul dynasty in 1526 where it was the jewel of jewels in the treasury of the Mogul emperors. In 1739 Nadir Shah of Persia invaded India, looted the Mogul palace and looked for the famous diamond. He was told that the emperor had hidden the diamond in his turban. Nadir Shah held a feast and offered a trade of turbans as a sign of peace. The emperor complied and Nadir Shah later unrolled the turban, found the brilliant gem and explaimed “Koh-i-noor” the Mountain of Light. Nadir Shah was later assassinated and his son died by torture rather than give up the diamond. Eventually it passed to other rulers – the Afghans, the Sikhs and finally the British who found it in the treasury at Lahore. Queen Victoria had it recut and it now resides in the Tower of London.
The Cullinan IV – cut from the same gem rough as the Cullinan I, this stone is 63.60
carats of a marquise shape and is in Queen Mary’s crown but is removable and can also be worn as a brooch.
The Florentine – a yellow diamond of 137.27 carats. It belonged to the Medici family
in the mid 1600s and appared in the Habsburg crown in the 18th century. Location lost after World War I
Metaphysical
As a symbol of purity its light bonds relationships and brings love and clarity to a partnership. A stone of manifestation it attracts abundance. It also enhances the power of other stones. It can also increase negative energy as well as positive. Imparts fearlessness and fortitude, clears pain and brings about new beginnings. It is creative, stimulating the imagination. For healing purposes it is believed to clear sight, benefit the brain, treat allergies and rebalances the metabolism. It was traditionally used to counteract poisons.
Dumorterite
Colour: dark blue, violet blue, red-brown and colourless
Hardness: 7-8.5
Cleavage: good
Fracture: conchoidal
Crystal system: orthorhombic usually found in a massive form.
Chemical composition: aluminium borate silicate
Transparency: transparent to opaque
Named after a French palaeontologist M E Dumortier. It can also be found intergrown with rock crystal quartz.
Found in Brazil, France, India, Canada, Madagascar, Mozambique, Namibia, Norway, Poland, Italy, Sri Lanka and the USA. Can be confused with azurite, lapis lazuli and sodalite.
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