What Opal Rough To Learn Opal Cutting And Polishing?

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This article is written to help cutters of all skill levels choose the best rough opal to cut and polish with.

Cutting Opal from the rough into a finished stone is very rewarding, but as a beginner it can seem a little bit daunting to figure out what type of opal rough to choose.

First you will require opal cutting and polishing equipment. A basic saw blade and different size polishing grit wheels from steel to rubber impregnated with diamonds in different grades and a polishing wheel.

Lets take a closer look at some of the options.

Rough Opal Types

Mixed parcels of rough opal around $20 to $50 are good to start from Koroit, Ethiopia or Coober Pedy rough. Ironstone with good patterns from Koroit and Yowah opal rough are good to learn polishing, if you polish to hard you wont rub away opal color. Yowah nuts are rock shaped and have strong colors, but it is said only one in a thousand has any color.

Ethiopian rough opals have thick color bars and are good value as it is inexpensive to purchase. So start with a plain patterned on your first purchases and inform yourself about hydrophane properties of this opal especially when polishing in water.

Boulder opal have many thin veins of color and can be difficult to polish with new wheels, this results to cutters rubbing away a lot of color trying to obtain a good finish. In some occasions, Boulder opal rough also needs to be split open by placing it in a saw cutter.

Black opal rough from lighting ridge can be very tricky. Black opal rough comes in two forms, seam opal or nobby opal. Seam opal is formed in layers and is best to learn on as the color bar sits on bottom potch. Most this potch is grey in color and has a body tone N4 to N5 and opal needs body tone N4 and above to be classed as black opal. Most black opal mined at Cochran is called nobby opal. This opal can be expensive and is formed like rock with color bar and can be difficult to read how to cut and polish. Many cutters make mistake of rubbing down the wrong side so when purchasing parcel always start off with cheapest pieces to see how the color faces. Even try cutting on angle to expose the best fire color, clarity of color is more important than size with good black opal. Many opal cutters will say they break even or loose on half rough opal they buy but do well with the other 50%.

So when buying opals that show color bars, you might think why hasn’t the miner rubbed it away? So veined rough has to be viewed as a gamble purchase, but win or loose it is still a fantastic hobby to cut and polish your own opals and set it in jewelry for family and friends.

The parcel below displays a lot of blue to green color in crystal. All opal miners look for nobbies for color formed on potch. Potch is basically opal that is one colored ie just white, just black etc. It is the most common type of opal what we want to find is precious opal that display many colors. Some of these chunks will display opal bars but it’s difficult to check when its in this rough condition. Larger pieces are sawed in two on a rough cutting wheel in order to expose any color.

Opal Rough For New Cutters

New opal cutters are best to start with boulder ironstone or Koroit opal rough. Alternatively Ethiopian Rough opals is still reasonable price at present and as the crystal color bars are thick, it is good for new cutters.

Once you have cut a few hundred opals and have good polish with no scratches than best to buy boulder opal rough with thin color bars to see how good you can rub down and keep as much color as possible.

Some black opals may contain shells or fossils and these are best not cut or polished but left natural. Coober Pedy has more fossils and shells and these have been popular as inlay rough material or for making doublets and triplets.

Rough Opal For Experienced Cutters

Experienced cutters can then purchase black opal rough as a parcel lot. As with all rough it is best to cut the most promising piece rough last not first! Many cutters are keen to see what the rough opal will expose but its always best to do smaller pieces so you get a better feel for the parcel. This is not as easy as it sounds as most opal factories use expensive ultra sonic drills.

Diamond tip drills are now relativity inexpensive but a cutter needs to take care when pushing drills through to other side (especially when trying to make beads) as a hole needs to be made from both ends or opal can chip.

Rough Opals conceal dazzling beauty, a hint of which is revealed by dipping the stone in water (as the sellers do; your rough opal(s) will arrive dry). A basic saw blade and good polish are essential to revealing the beauty of a rough opal, as are patience and time. If polished correctly, some opals reveal a bright fire color. These dazzling color bars can be rubbed away if polished too roughly.

Opal-cutting lapidary machines are available for purchase but may not be necessary if you can make your own.

Rough opal can be sourced directly from opal miners and wholesalers/dealers. It is available from all the major Australian opal fields:

Ethiopian rough opals were hard to obtain as the government ban the export of Ethiopian rough around mid 2013 and only allow cut stones to be exported. Fortunately they have now changed this policy, although they have implemented high tax on exports.

Buying Rough Opal On The Internet

I have seen many new cutters go straight out and buy parcel rough black opal and start cutting. Unfortunately they rub away a lot of colour trying to get a good polish. This is due to three reasons. Firstly, lack of experience. Two, they don’t know how to polish and three, new wheels. Most cutters have new wheels and don’t realise how sharp these diamond tip wheels are and leave big scratches in the opal. So when they polished the colour bar is rubbed away.

It’s best is to start with rough opal from Koroit opal rough, Yowah opal rough, or Ethiopian rough and choose between middle to low grade opal rough. This is easy to polish as you don’t have to follow colour bars. It’s a little bit messy and you will get brown stains but you can tell when the polish is good on the opals.

Next is to try Coober Pedy white opal rough as they have thick colour bars to rub down. Then go and try boulder opal rough or black opal rough with thin colour bars.

Remember to always rub the worst looking rough in parcel, never start with the best promising pieces of rough. Pick out the best looking rough opal and leave it aside then rub and polish the lower grade. This will help you get the feel of the parcel. Sometimes cutters get the location of the top and bottom of the opal mixed up. So it’s best to experiment on low grade before you cut the good opals.

Buy volume parcels and get experience. If diamond wheels are too sharp, then try to rub down the wheel to get it smooth with any tough stone like Agate gemstone and make sure you rub down evenly with plenty of water.

Semi black or grey rough is good to start for Lightning Ridge material. Sometimes the centres of the rough are black, so if you’re cutting these go for a smaller black opal instead of large grey based opals.

Today the best way to buy opals is to buy on the internet or go direct to the opal fields in Australia and dig your own opal. In the past opal miners and opal wholesalers would visits shows like Tucson in USA but today these shows are so expensive to go as a seller. Booth and travel costs are well over $20,000 now, and that’s only for one person. Now opal miners and opal dealers prefer to offer you opals at wholesale prices from the internet. So make sure you buy from an opal dealer with good feedback and who stand behind their product. Most opal miners and opal wholesalers are honest, hard working, and have a genuine passion for opals.

Ask as many questions as your comfortable with as to where the opal came from and ask if the image is accurate like the picture.

SHOP FOR OPAL ROUGH

Rough Opal

Ovaj je članak napisan kako bi se omogućilo reznicama svih razina vještina u odabiru najboljeg grubog opala za rezanje i poliranje.

Rezanje opala iz grube u gotov kamen vrlo je korisno, no kao početniku može se činiti pomalo zastrašujuće shvatiti koju opal grubu opciju odabrati.

Prvo ćete trebati opremu za rezanje i poliranje. Osnovna lista pile i kotači za poliranje različitih veličina od čelika do gume impregnirani dijamantima različitih razreda i kotačić za poliranje.

Pogledajmo bliže neke od opcija.

Grube vrste opal

Mješovite parcele s grubim opalom oko 20 do 50 dolara dobro je započeti od grube Koroita, Etiopije ili Coober Pedy-a. Ironstone s dobrim uzorcima iz Koroita i Yowah opala grubi su dobri za naučiti poliranje, ako ih polirate tvrdo, nećete trljati opal boju. Yowah orašasti plodovi su u kamenu i imaju jake boje, ali kaže se da samo jedan od tisuću ima bilo koju boju.

Etiopski grubi opali imaju guste šipke u boji i dobra su vrijednost jer ih je jeftino kupiti. Zato počnite s običnim uzorkom na svojim prvim kupnjama i informirajte se o hidrofanskim svojstvima ovog opala, posebno prilikom poliranja u vodi.

Boulder opal ima mnogo tankih vena u boji i može ih biti teško polirati novim kotačima, a to rezultira time da rezači trljaju puno boje pokušavajući postići dobar finiš. U nekim prilikama, Boulder opal grubo također je potrebno rascijepiti stavljanjem u rezač pile.

Crni opal hrapav s rasvjetnog grebena može biti vrlo lukav. Crni opal grubi dolazi u dva oblika, šav opal ili nobby opal. Opal za šavove formira se u slojevima i najbolje je učiti dok traka boja sjedi na dnu potkrovlja. Većina ovog saksija je sive boje i ima tjelesni ton N4 do N5, a opal treba tjelesni ton N4 i više da bi se mogao klasificirati kao crni opal. Većina crnog opala koji se minira u Cochranu naziva se nobby opal. Ovaj opal može biti skup i nastaje poput stijena s trakom u boji, a može biti i teško čitati kako rezati i polirati. Mnogi rezači pogriješe trljajući krivu stranu pa pri kupnji paketa uvijek započnite s najjeftinijim komadima kako biste vidjeli kako se boja suočava. Čak pokušajte smanjiti kut kako biste izložili najbolju boju vatre, jasnoća boje je važnija od veličine s dobrim crnim opalom. Mnogi rezači za opal reći će da se lome ili izgube na pola grubog opal-a koji kupuju, ali da je dobro s ostalim 50%.

Pa biste, kupujući opale koji prikazuju trake u boji, mogli pomisliti zašto ga rudar nije protrljao? Tako prošaran grubo treba gledati kao kupnju kockanja, ali pobjeda ili gubitak fantastičan je hobi rezanje i poliranje vlastitih opala i postavljanje u nakit za obitelj i prijatelje.

Paket ispod pokazuje puno plave do zelene boje u kristalima. Svi opalni rudari traže nobelove za boje nastale na loncu. Potch je u osnovi opal koji je obojen, tj. Bijeli, samo crni itd. To je najčešća vrsta opala. Ono što želimo pronaći je dragocjeni opal koji prikazuje mnogo boja. Neki od ovih komada prikazat će opalne šipke, ali teško je provjeriti kada je stanje u ovom grubom stanju. Veći komadi se rezavaju po dva na grubom kolu za rezanje kako bi se otkrila bilo koja boja.

Opal Grubo za nove rezače

Nove rezače za opal najbolje je započeti s gvozdenom kamenom od kamena ili Koroit opal grubo. Alternativno, etiopski grubi opali su i dalje prihvatljive cijene, a kako su kristalne šipke u boji debele, dobro je za nove rezače.

Nakon što ste izrezali nekoliko stotina opala i dobro polirali bez ogrebotina, najbolje je kupiti gomoljasti opal grub s tankim trakama u boji kako biste vidjeli koliko dobro možete trljati i zadržati što više boje.

Neki crni opali mogu sadržavati školjke ili fosile, a to je najbolje ne rezati ili polirati, već ostaviti prirodne. Coober Pedy ima više fosila i školjki, a oni su bili popularni kao ugrađeni grubi materijal ili za izradu duple i trosjeda.

Grubi opal za iskusne rezače

Iskusni rezači tada mogu kupiti crni opal grubi grud kao paket. Kao i kod svih grubih, najperspektivnije je najprije izrezati posljednji, ne prvi! Mnoge rezači žele vidjeti što će grubi opali izložiti, ali uvijek je najbolje raditi manje komade kako biste dobili bolji osjećaj za parcelu. To nije tako lako kako zvuči, jer većina tvornica opal koristi skupe ultrazvučne bušilice.

Dijamantne bušilice sada su relativnosti jeftine, ali rezač treba voditi računa kada gurnete bušilice na drugu stranu (posebno kada pokušavate napraviti perlice), jer rupa treba biti napravljena s oba kraja ili se opal može usitniti.

Grubi opali skrivaju zasljepljujuću ljepotu, čiji se nagovještaj otkriva potapanjem kamena u vodu (kao što to rade prodavači; vaši grubi opal (i) postat će suvi). Osnovna lista pile i dobar lak neophodni su za otkrivanje ljepote grubog opala, kao i strpljenje i vrijeme. Ako se pravilno poliraju, neki opali otkrivaju svijetlu boju vatre. Ove zasljepljujuće šipke u boji mogu se protrljati ako ih grubo polirate.

Lapidarni strojevi za rezanje opalom dostupni su za kupnju, ali možda nisu potrebni ako možete napraviti svoje.

Grubi opal se može dobiti izravno od rudara opala i trgovaca na veliko / distributera. Dostupna je sa svih glavnih australskih polja opala:

Teške je bilo dobiti etiopske grube opale jer je vlada sredinom 2013. zabranila izvoz etiopske sirove robe i omogućila izvoz samo rezanog kamenja. Srećom oni su sada promijenili ovu politiku, iako su uveli visok porez na izvoz.

Kupnja grubog opala na Internetu

Vidio sam kako mnogi novi rezači idu ravno i kupuju parcelu grubi crni opal i počinju sa rezanjem. Nažalost, trljaju puno boje pokušavajući doći do dobrog laka. To je zbog tri razloga. Prvo, nedostatak iskustva. Dva, ne znaju kako polirati i tri, nova kotača. Većina rezača ima nove kotače i ne shvaćaju koliko su ovi dijamantski vrhovi kotača i ostavljaju velike ogrebotine u opalu. Pa kad se poliraju traka u boji se briše.

Najbolje je započeti s grubim opalom od Koroit opal Grube, Yowah opal grubim ili Etiopskim grubim i birati između opalnog grubog od srednje do niske razine. To je lako polirati jer ne morate slijediti trake u boji. Malo je neuredan i dobit ćete smeđe mrlje, ali možete reći kada je lak dobar na opalama.

Sljedeće je isprobati Coober Pedy bijeli opal grubi jer imaju guste šipke u boji. Zatim krenite i isprobajte gromobransku oplaku od grube ili crne boje opala s tankim šipkama u boji.

Ne zaboravite da u paketu uvijek trljate najgori izgled grubo, nikad ne započinjte s najboljim komadima koji obećavaju. Izaberite najprikladniji opal i ostavite ga po strani, a zatim ga protrljajte i polirajte niži razred. Ovo će vam pomoći da osjetite paket. Katkad rezači miješaju mjesto vrha i dna opala. Zato je najbolje eksperimentirati na niskoj ocjeni prije nego što izrežete dobre opale.

Kupite paket paketa i iskoristite iskustvo. Ako su dijamantski kotači preoštri, pokušajte trljati kotač da biste ga izgladili bilo kojim čvrstim kamenom poput dragulja Agate i pobrinite se da ravnomjerno trljate s puno vode.

Polu crna ili siva hrapava je dobro pokrenuti za materijal Lightning Ridge. Ponekad su središta grube crne boje, pa ako ih sečete, prijeđite na manji crni opal umjesto na velike opal na sivoj osnovi.

Danas je najbolji način za kupnju opala kupiti na internetu ili otići izravno na polja opala u Australiji i iskopati svoj vlastiti opaal. U prošlosti su rudari opal-a i veletrgovci opal-a posjećivali predstave poput Tucsona u SAD-u, ali danas su te emisije toliko skupe da bi se prodavale. Troškovi kabine i putnih troškova sada prelaze 20 000 američkih dolara i to samo za jednu osobu. Sada opal rudari i trgovci opalima radije nude vam opals po veleprodajnim cijenama s interneta. Pa se obavezno kupite od prodavača opala s dobrim povratnim informacijama i tko stoji iza njihovog proizvoda. Većina rudara opala i veletrgovaca opala pošteni su, marljivi i imaju istinsku strast prema opalima.

Postavljajte što više pitanja s obzirom na to odakle je opali i pitajte je li slika točna kao na slici.