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Semi Precious Stones used in Jewellery making. Many stones are used to produce jewellery. Here is some information about some of the most popular. Amethyst Origin. The finest amethyst forms in geodes (gas cavities) in volcanic rocks. Crystals that are part amethyst and part citrine are called ametrine. Colour. Shades of purple, lilac and mauve, transparent, translucent and opaque. Inclusions Common Sources Amethyst comes from around the world, including Cornwall, parts of Africa, South America, Russia, S.E.Asia and China. Crystals source their rough amethyst geodes, cones and beds from Brazil although significant amounts are from Uruguay (traded through Brazil). Amethyst used in jewellery settings comes additionally from a number of African countries and occasionally from elsewhere. The very deep/dark amethyst is commonly African, i.e. South Africa, Zaire and Namibia. Stones are cut in many countries. Amber Succinite = Baltic Amber Origin. Sub-tropical forests existing 30 - 50 million years ago in the Baltic region contained various tree species (especially pines) that produced a sticky resin from their bark. This gradually dripped down the trunk, collecting in small ‘pools' on the forest floor. Air bubbles were often trapped, as were numerous other items. The resin slowly dried and solidified to form a fossilized resin aftercovering and compaction by forest sediments. Rivers were responsible for moving some amber to the coast, from where it was distributed by sea, even reaching the beaches in eastern England. Some amber deposits lie in sediments extending out under the Baltic Sea. Pieces can become dislodged in storms and float away. Colour. Many shades of yellow / brown. It can be transparent, translucent or opaque. ‘Cognac' refers to the rich orange red, ‘Golden' to golden yellow, ‘Buttermilk' or ‘Candy' to opaque cream amber and ‘Green' to a specially prepared form. Raw amber pieces often have a reddish brown colour due to surface oxidation in the air. Inclusions. Amber inclusions have provided scientists with superbly preserved evidence of forest plants and animals living millions of years ago (many of which are now extinct) which became ‘trapped' in sticky resin. Specimens have been found with perfectly preserved: - insects such as flies, ants, spiders, bees (sometimes with full pollen sacks), mayflies, mosquitoes, moths, grasshoppers etc.
- small animals such as frogs, lizards, bird feathers, snakeskin or footprint impressions
- mosses, mushrooms and algae
- pieces from higher plants such as leaves, twigs, flowers, buds, bark, cones and pollen. Fake inclusions from Russia are commonplace (scorpions are a favourite!).
Air bubbles are a common inclusion and during amber preparation may form the ‘sun bursts/sun spangles' which look like circular shiny fish scales. Exceptional pieces may contain a water droplet trapped in an air pocket - this would be REALLY old water!! Sources. In The Pink amber is 90% from Kaliningrad (Russia) with the rest coming from Lithuania, Latvia and Poland. The amber tends to be calibrated, smaller sizes in contrast to the individual pieces that are handmade. However, some handmade amber jewellery uses pre-cast components which are then hand finished. Sourcing amber is a fraught undertaking for manufacturers. Environmental restrictions by local authorities in Gdansk mean that huge deposits are largely left untouched. This has resulted in the majority of amber coming from Russia. Sadly, the frontier town mentality and criminal elements make it nearly impossible to buy from Russian silver manufacturers. Much ‘cheap' street/market amber jewellery comes from these sources. Russian amber is also exported ‘raw' to Poland where it is cut, cleaned and prepared for jewellery manufacture. Historical Amber. Historically amber has been prized for use as ornaments, jewellery, totemic objects and in various medicinal preparations. Polish museums are treasure troves of fine examples, especially in Warsaw and Gdansk. Theories. about amber's origin that have been dispproved. . . . Sadly it has proved NOT to be:
- tears from gods and mermaids
- condensed sea foam
- solidified lynx urine!
- wax from wood ants
- modified honey
- solidified sun's rays at dusk Aquamarine Origin. Aquamarine (a variety of Beryl) forms in large grained igneous rocks and is occasionally found in river gravel deposits. Crystals up to 1m in length have been found. This beautiful stone was used in the ancient Greek and Roman Civilisations from 3rd century BC. Colour. The range of greeny blue to pure blue colours are due to tiny amounts of iron impurities. Aquamarine (literally meaning ‘sea water') can appear either blue or colourless depending on the angle of viewing. Sources Crystals aquamarine comes from many countries including Afghanistan, Pakistan, Central Africa, Brazil and occasionally Russia. The story! Aquamarine causes passionate discussion amongst people. What colour is best? Are small exquisite samples from the rural former colonial outposts of the Hunza Valley (Himalayas) better than larger well defined specimens from Zaire or Minas Gerais? Who knows! Several samples appear as book illustrations. A very difficult crystal to purchase both in rough and cut form with prices and quality varying enormously. Colour varies from various shades of blue to green. There is no ‘best' colour or crystal form. Whilst clarity is important, you can enjoy pieces with unusual inclusions such as black tourmaline. Aquamarine is a joy a truly inspirational stone. Rainbows and inclusions all add to the appeal. Opal Origin. Forms very slowly in sedimentary rocks (e.g. sandstone) where water is present. Colours. ‘Precious opals' all show some internal ‘colour play' / ‘flashes' Blue / green opals are very popular, those containing reds / oranges /violets usually demand a premium. ‘Fire opals' refer to red / orange clear opals (NOT from the internal flashes mentioned above). Sources opals are from the extremely hot, dry centre of Australia where the opal miners not only extract opal under-ground, their houses are also underground! History Shakespeare referred to opal as ‘the queen of gems' in Twelfth Night. Pliny, in Roman times described opal as having ‘the fire of the carbuncle, the brilliant purple of the amethyst and the sea green of the emerald all shining together in incredible union'. The Arabs believed opals fell from Heaven in flashes of lightning, gaining their fiery flashes as they fell. Story. Opals can be somewhat controversial - unlucky? This idea has come about from people not knowing how to look after opal stones. Opals are beautiful, inspirational and suited to everyone! Obviously their properties may result in careless owners suffering damage - a natural consequence of their own behaviour NOT opals being unlucky. It is also said that the opal cutters were always the poorest of the stone cutters as opals are easy to damage during cutting (so the cutters' profits would be lost). HOW TO CARE FOR OPALS The particular characteristics of opals mean that certain rules must be followed to keep the stones in good condition:
-Avoid scratching the relatively soft surface
-Avoid very high temperatures (e.g. very hot water) or extreme low humidity (e.g. bank vaults!)
-Clean, if necessary, with mild detergent and a damp cloth or soft toothbrush
-If storing for long periods, pop in cotton wool in a sealed plastic bag with a few drops of water. Labradorite Origin. Labradorite forms in igneous and metamorphic rocks in various parts of the world, being discovered in Labrador (NE Canada in the 18th century). Colour. Colourless or grey but displaying a spectacular play of colour or ‘schiller' (from the German word for iridescence) caused by interference effects of light either bouncing off tiny particles of magnetite impurities or from being refracted back and forth between layers formed within the specimen. The ‘labradoresence' is usually blues, purples, greens, golds and sometimes reds. Sources. Labradorite comes from Madagascar Peridot. (Pronounced perry - doe) Origin. Peridot is gem quality olivine, a mineral that forms at high temperatures in volcanic rocks such as basalt. Colour. Olive or bottle green, transparent Sources. Peridot comes from Brazil and occasionally from other sources. Additionally. Peridot has always been associated with the month of August/Leo.. Why? What about the other eleven months - it is absurd to imagine that peridot is only suited to 8.33% of the population. However, it is likely that traditions (many dating from the 19th century German jewellery trade!) will prove enduring and that sales in August and to Leos will remain high! Most peridot crystals are small. It is now almost impossible to buy large cut stones with large beads disappearing completely. Because of difficulties with supplies the results will be higher prices and smaller stone sizes. No doubt fashion will continue to swing from light to dark green. Stones with rutile inclusions are rare and especially beautiful. Quartz Origin. Imagine ice that had been frozen so hard into crystals by the gods that it would never melt . . . this was the ‘explanation' for quartz for centuries. The Greek word kyros (meaning icy cold) is the origin of our word crystal.Quartz crystals form when silica rich molten rock cools down. It is found worldwide and makes up over one tenth of the Earth's crust. Colour. Clear quartz / rock crystal is colourless and transparent, often with beautiful fleeting rainbows. ‘Herkimer diamonds' are exceptionally clear, completely terminated crystals that were formed in liquid suspension and originally discovered in Herkimer County, New York State. Inclusions. Rutilated quartz contains needle-like rutile crystals of golden, orange or red colour - explaining the popular name of Venus Hair Stone. Tourmalinated quartz contains fine or thicker needle-like black tourmaline crystals, usually black, but, rarely green or pink. Sources. Crystals quartz comes from every continent, from the peaks of the Himalayas to the deserts of Arizona. In Minas Gerais there are significant quartz deposits including many special formations, such as Smoky celestial, natural citrine cathedrals and tourmalinated quartz. An inspiring task is been to watch the cutting of boulder quartz into spheres, obelisks, wands and pyramids. Immense skill shown by multi-generational families leaves one breathless.A modest house, a coffee in the kitchen and a walk into the rear yard. Then suddenly the magnificent collection of, say, lazer crystals. At present Japanese buyers are prepared to buy wholesale consignments of AA Grade rutile quartz in Brazil for more than would be typically charged in shops in the UK. When crystal healing is ‘fashionable' prices can rise sharply. A downturn sees craftsmen moving and leaving quartz cutting. This is the cause of variable quality and pricing. For example pyramid cutting is not in fashion. Huge slabs of boulder quartz can be seen in the back of a lorry. Many beautiful pieces now grace colleagues' rooms, healing centres and stately houses. The value of quartz is very good and it is unlikely that these prices will ever be repeated. Also In 1880, the French Nobel physicist Pierre Curie (husband of Marie) discovered that quartz is piezoelectric - that is it will produce an electric charge on its surface when put under pressure from different directions. During the Second World War, quartz was heavily used in radio transmissions - it was this demand that led to the development of synthetic quartz. Rosequartz Origin. Rose quartz is found in sedimentary rocks such as sandstones and in beach and river deposits. Occasionally found in geodes (gas cavities). Colour. Pale to mid pink. Generally opaque or translucent. Transparent rose quartz is very rare. Sources. Crystals rose quartz comes from a number of locations: Gem specimens - Madagascar. This can have a lilac hue and is generally translucent. Rock specimens - Brazil. Topaz Origin. Topaz forms at high temperatures, often in association with quartz, in igneous rocks such as granite and volcanic lavas. The name may come from the Sanskrit word ‘tapas' meaning fire. Colour. Pale blue, pale pink, pale green or a yellow to golden brown, called imperial topaz. Transparent or slightly translucent if streaked/veiled or containing tear shaped gas or liquid bubbles. Sources. Blue topaz is found world wide although orange imperial topaz is unique to Brazil. Blue topaz is widely found in boulder and crystal form and is heat treated to produce a very deep blue colour. However, as the Natural History Museum topaz display makes clear there is no ‘test' for heat treated topaz and it is therefore sold as ‘natural'. Additionally, the largest topaz specimen ever discovered (in Madagascar) weighed over 2.5 tonnes! The ancient Egyptians associated golden topaz with the glow of their mighty sun god Ra. Likewise, Romans linked topaz with their sun god, Jupiter. Tourmaline Origin. Tourmaline is a family of minerals with closely related chemical compositions. They form in igneous (volcanic) and metamorphic rocks and are occasionally formed in alluvial deposits and sedimentary rocks. Colour. Tourmaline shows the greatest range of colours of any gemstone and can show spectacular multicoloured bands within a crystal. Can be translucent or opaque. Available in the following colours for specimens and jewellery: green, pink, watermelon (pink and green), black and particularly sought after blue. Sources. Tourmaline comes from many countries. Presently most tourmaline is from Madagascar, Pakistan and Brazil (Minas Gerais). Tourmaline was widely mined in Cornwall and can be found in many museums in our towns. Tourmaline specimens have been collected for over 200 years. Examples can be viewed at the Natural History Museum (London). Cut stones command a king's ransom when exhibiting flawless surfaces and perfect cutting. Tourmalina is a Brazilian town with numerous mines. Russia also has mining settlements named after this important mineral. Bi-coloured and watermelon are always popular but not easily found. Inclusions of black tourmaline in quartz look especially mysterious and dramatic, especially when draped upon a beautiful body. Jade Origin. During the Stone Age of many cultures, jade was used for axe heads, knives, and other weapons. As metal-working technologies became available, jade's beauty made it valuable for ornaments and decorative objects Structure. Jade has a hardness of between 6.5 and 7.0 on the Mohs scale, so it can be worked with quartz or garnet sand, and polished with bamboo or even ground jade. Sources. Jade comes from many countries> Most notable is Korea and New Zealand. Jade is the official gemstone of British Columbia and is found in large deposits in the Lillooet and Cassiar regions.
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