Opal production has decreased over the last decade. Demand has risen. More people are working the opal fields with greater mechanisation. Opal is like other resources- we are exhausting the existing known supplies and hoping new strikes will be found. The mining of opal is done by individuals or syndicates- no large companies are mining any of the fields. Stockpiling of the gem therefore cannot occur: this means that prices are a true reflection of market demand.
Opal as an investment will be a very good investment. The value of these gems can only increase as the better quality stones are becoming rarer to find.
A GUIDE TO OPAL
Nature has captured all the colours of the spectrum, displaying them in an infinite variety of shades, patterns and brilliance and locked then into this rare stone.
Opals lie dormant in the earth until a miner clips the edge and the light reaches the gem exposing the most beautiful dancing display of colours.
Since ancient times opal has been sought by many famous collectors including Mark Antony Pliny and Queen Victoria.This precious gem was even included in the crown of the Holy Roman Emperor. Australia produces at least 95% of the worlds precious opal which with its increasing scarity , is amongst the most sought after and precious of all gems. Quality black opals can fetch prices equivalent to good diamonds on a per carot basis.
History states that Ancient Romans cherished opals above all other gemstones- not just because they were rare and beautiful gems- but because they were thought to bring good fortune. Indeed fortunes were paid for these gems. Mark Antony offered Senator Nonius 100,000 sesterces for a brilliant opal (AUD$1,000,000 IN TODAYS VALUE). Nonius however would not part with his tallisman, his own personal rainbow ensuring his lucky future.
PLAY OF COLOUR.
An opals beauty is unique and made from the amazing " play of spectral colours" in the gemstone. This originates from the breaking up of white light due to the three dimensional spherical shaped microstructure of the silica particles inherent in the opal (these can only be detected with an electon microscope) Similar phenomena of colour hues can be observed when oil lies on water , or in a rainbow.
Opal occurs where silica gel fills small fissures or voids in the earth. A large portion of Australias inland was once covered by a sea, leaving deposits and creating an envirorment suitable for the formation of opal.
TYPES OF OPAL
Natural opal is divided into catergories of black, dark, light boulder and matrix opal. The classification of black, dark and light is determined by the body tone ie. the degree of darkness in the background.
FACTORS DETERMINING VALUE
THE BRILLIANCE of colours is of paramount importance-the brightness of an opal is directly related to price.
THE PATTERNS of colours when combined with brilliance may increase value many times.
COLOURS : the number of different colours affects price although this rule would be used with great care.An opal with all the colours of the spectrum is not always more valuable than one displaying red/blue or green/blue alone, because major determination of value is brilliance and patterns.
SHAPE: usually cut en cabochors, a stone with a domed surface will be more valuable than a similar stone with a flat surface. Opal which is too thin could fracture on impact. While oval stones may show a great demand, boulder opals often cut in free shapes can lend themselves to more distinctive designs.
MARKS: most opals, particularly black, have sand in the back of the stones. This usually does not affect the value. However, marks or cracks that are fully noticeable in the face of the stone will drastically affect value.
LOOKING AFTER YOUR OPAL.
Although opals are a magnificent and unique gem they do not have the resitance to breaking or scratching that diamonds or saphires have. If you protect your stone from heavy blows, and abrasive material, and dont subject it to extreme sudden heat changes , your opal should last forever.
If you have an opal doublet or triplet, never immerse it in detergents(and preferably not even water) as this may break down the adhesive quality of the glues that have been used and cause separation .(or lifting)
ALL INFO ON THIS PAGE WITH COMPLIMENTS FROM YOUR JAA JEWELLER.
Black opal is the most valuable and comes mainly from Lghtning Ridge. High quality stones are very rare: this type is easily distinguished by the blackness of the base or background 'body tone'.
BLACK CRYSTAL OPAL:
Black crystal opal is mainly mined at Lightning Ridge. These black opals show a degree of transparency, the colours are often brilliant and can appear to come from within the depth of the gemstone. Good black crystal opals are very rare.
Dark opal comes from all fields and is desirable because the colours are generally more brilliant, due to the dark background 'highlighting ' their colours. This type of opal mainly comes from Mintabie in sth aust and Lightning Ridge N.S.W
Light opal is usually found at all opal fields but the bulk of the material has come from the SOUTH AUSTRALIAN fields of MINTABIE , COOPERPEDY and ANDAMOOKA although the first material was mined at WHITE CLIFFS(1887). This opal has a light body tone.
This variety embraces opal which is transparent or very translucent and in the better qualities shows a distinct and very bright play of colours. This type of opal is found at most Australian opal fields.
This type, composed of opal naturally occuring on its host rock, is mined predominatly in QUEENSLAND it is easily identified because when cut the host (a brown ironstone) is left on the back of the opal. Boulder opal may be light dark or black. In the last twenty years this type of opal has become extreemly popular as it can display the same darkness and brilliance as a high quality black opal.
There are two common types of Matrix Opal in Australia.
A: BOULDER MATRIX OPAL is usually found in Queensland. The opal intimately diffused with the host rock. (usually ironstone) The host rock is quite obvious in the presentation face of the stone.
B: MATRIX OPAL from ANDAMOOKA has opal infinately diffused throughout the host rock , a sandstone which is often porous and can be treated, turning the material dark resembling black opal.
COMPOSITE NATURAL OPAL:
Composite natural opal consists of a natural opal laminate, manually cemented or attached to another material. There are three main forms of composite opal.
A composition of two pieces where a slice of natural opal is cemented to a base material.
A composite of three pieces where a thin slice of natural opal is cemented between a dark base material and a transparent top layer (usually of quartz or glass)
MOSIAC AND CHIP OPAL:
A composition of small flat or irregularly shaped pieces of natural opal cemented in a mosiac tile on a dark base material or encompassed in resin.
SYNTHETIC AND IMITATION OPAL:
Occasionally offered for sale: however the laws in Australa require the retailer to inform the purchaser of this fact. Most opal sellers do not handle synthetics or imitations.