83g Koroit Boulder Queensland Opal Australian Rough Nut piece Green fire Bo-124

Description: CORNWALL GEM TRADER UK SUPPLIER - based in Cornwall A chunk of a Koroit Queensland boulder opal nut, Sliced to show beautiful natural pattern with some rubbed sides. Interesting green blue green opal fire area with vein patterns on the other side. Keep as a specimen or slice up to make many cabochons Piece shown wet UK buyers pay NO import duties as our stock is UK based Source - Queensland Koroit Size - 70x55x25mmWeight - 415 carats - 83gBase Tone - IronstoneFire Colour - Blue GreenBrightness - 4/51 - Country of origin and the mine the material was dug from2 - The dimensions of the opal in mm or the average size if rough pieces 3 - The weight of the item in carats (5 carats = 1 Gram, 31 grams = 1 Troy Oz, 1000 grams = 1 kilo)4 - The colour of the Opals Body Tone N1 - N4 - Is for black tone body types. Body Tone N5 - N9 - Is for lighter coloured Opals.5 - The colour of the precious opal produces when in a direct bright light source, this can change from sunlight to artificial light.6 - How bright the fire colour is to the eye, from 5 being the brightest down to 1 being the dullest. These are graded like 4 out of 5 eg 4/5. All orders are sent tracked unless stated otherwise, its the reason we charge for shipping as its not cheap but having your precious opal arrive safe is important to us. Opal will arrive in a clear sealed plastic wallet, please view the opal in the wallet removing the opal will mean you can not return the item as it will be classed as touched/altered. There is a tamper seal sticker please leave in place to return opal.Delivery times in the Uk are normally around 3-5 works daysInternational orders are 7-21 working days (hold ups in customs may make this longer until you have paid your import duty) We have sold Opal for over 25 years and have cut 10,000's of opal stones in our workshop right here in the UK. Based in Cornwall. We only sell Opal that we ourselves would cut, we do not sell off worthless mine run material like other sellers on eBay. (watch out for the ones saying gamble rough, no/little colour etc you are just buying worthless potch) We hold a large amount of rough and cut stones, you can contact us here or via details in our bio. Please read all of the below before buying any of our opal.When opal arrives and you are not 100% happy you can return for refund.If you cut/alter any piece you are accepting ownership and the opal can not be returned (no cherry picking)Negative or neutral feedback cannot be left if you do not understand what you are cutting or buying - Any questions just ask we are happy to help, we rather help you with cutting so you come back than have a negative experience. Please note not all opal will produce its part of the cutting game. Negative feedback will be dealt with a lifetime ban.Please study carefully before cutting.Images of the rough opals are taken wet and either in sunlight or a light set up to represent sunlight. Remember Opal is a sun stone so needs light to come alive 100%Buyers claiming parcels do not arrive to get a refund will be banned for life, it may be tempting to try and get free opal but remember I have kids to feed as well.Any questions about an auction, please ask before buying. Happy to help you.International Buyers - Buyer is responsible for any customs/import Duty or taxes levied in the buyers country. How is Opal Colour Produced?Opal formationThe local name given potch, such as desert sandstone, is dependent upon the area in which they occur, but they all belong to the same families of felspathic sandstone, claystone, siltstone and mudstone, which are said to have been deposited over large areas buy streams and lakes.We call any material that opal colour has formed on as Potch. Except for volcanic opal, which usually occurs in Tertiary rocks, all the types of opal we have come to know so well are found in these strata. Although the opal is found in the Cretaceous sediments, it is a matter of conjecture as to it?s deposition over millions of years during the Tertiary period. The general teaching is that certain minerals were broken down in the country rock to produce silica at 120 parts per million, and trace elements which were deposited in cavities left by bones, shells and other dissoluble material. These, as well as faults and fractures in the ground, provided pathways for the underground waters to carry the silica down at the end of the weathering period.Although this is the entrenched theory, with ?slight variations? depending on your source of information, it is fraught with problems which have been deleted from the model to give it credence. There is little doubt that all opal was not deposited in exactly the same manner. So far I have discovered four different ways in which it has been deposited; there may be more. They all have a common denominator in the equation, ionic-exchange. The fact is that opalization is extremely regional and that large beds of impervious barriers are only secondary to opal formation.If the only requisite for opalization under the above model were suitable impervious traps, then there would be massive beds of opal over vast areas. However, as every opal miner knows, this is not the case and all opal is unpredictable and patchy in the extreme.Australian Opal is rarely faceted, nearly always domed. A domed stone is stronger and less prone to chipping. However Opal without a play of colour (such as cherry red or amber Opal from Mexico) is often faceted and can look a lot like ruby. Opals are a carver?s delight. The stone is not too hard to work with and will not wear out your diamond tools as much as such stones as Chrysoprase and Agate.

Price: 149 GBP

Location: Helston

End Time: 2025-01-02T14:51:31.000Z

Shipping Cost: 37.97 GBP