There are many cutting machines and ways to cut and polish opal. Finding the opal-cutting machine that suites you is the question that most people have on their mind when starting out.
When choosing an opal-cutting machine you have to take into account whether you are going to use diamond grits to cut and polish your opal or sandpaper, pumice powder, and cerium oxide.
If you decide to go all out using diamond grits to cut and polish your opal, you will basically only need three opal cutting machines.
Firstly you will need an opal cutting machine like a pixie or here in Australia we have machine called Gemmasta. These machines are wet machines and will hold all of the diamond wheels you will need to rough shape and polish your opal.
The most commonly used diamond grit wheels in my opinion are as follows
Wheel1: 240 grit hard diamond wheel for roughing out your opal to the approximate size and shape of you want.
Wheel 2: 600 grit hard diamond wheel for the finer shaping on the dop stick to get the shape and dome you want the opal to have.
Their are very expensive diamond wheels on the market called sintered wheels which have diamond impregnated 3 to 4mm into the opal cutting wheel. I use these wheels and they have lasted my whole cutting career, so they are so worth the expense.
Wheel 3: A 1000 grit soft nova wheel for smoothening the opal and giving the opal it’s round smoother edges and dome.
Wheel 4: A soft 10,000 or 15,000 grit Nova wheel to give you a final polish,
The thing about diamond wheels is that you will probably have trouble getting a really good polish. They have not perfected the polishing stages yet in diamond.
My advice is to purchase flat lap felt wheel and use cerium oxide with water to brush the cerium oxide using a clean paint brush to apply it onto the felt wheel, that way you will get the best polish possible. (Always re-applying to keep it wet)
The way I cut and polish opal is using hard diamond grits to start with, but then once I have finely cut the opal to the approximate size and shape, I then change to a flat lap 1000 grit wet and dry sand paper with cushioning as backing. (You must wear the sandpaper down with potch to get the right smoothness) This technique is an old fashion way but still I think the best and cheapest way to go.
Always using this part of the process dry. (A dust mask is handy to use)
Once I have sanded the stone I use a felt wheel with pumice powder and water to get the pre-polish, final shaping and adjusting done.
Make sure you wash the opal and your hands really wel so you don’t get impurities in the final polish otherwise you will get scratches in your opal
And then I polish with cerium oxide to finish the opal.
The back of the stone is smoothened out by re-gluing the opal upside down on the dop stick and smoothing the back to as fine a polish as you would like, sometimes giving you a double sided polished opal.
Lastly to become a great opal cutter I think it is important to own a slicer, to slab or split and take excess opal that is not needed away from the nobby.
A slicer also helps when the rough opal piece would be better cut into 2 stones.
Or there is more than one colorbar in the piece.
Opal Tips
Tip Number 1
I hope this has been useful to you.
If you have a piece of rough opal and you can't see into it to see if the color-bar is clean. A really great tool for evaluating opal is to use a laser pointer. A laser pointer can actually assist you in peering into the depths of an opal rough piece. The beam when pointed into the color-bar will stop on any impurity, potch or opal that has no color. All you have to do is go into a dark room or shade (not sunlight) to see into the stone. This does not always work because some potch can be too black, but it does work most of the time. Once you have estimated where the impurities are in the opal, you can then start to figure out where the opal solid is to be cut out. With careful rubbing on a cutting wheel, you should have the first stage of the rubbing process done. If you don't have a laser pointer you can use a bright light but the light disperses alot more so it is harder to see into one particular area of the opal at a time. I have used a laser pointer for many years and has saved me thousands of dollars by showing up the inclusions that I would never have seen before with the naked eye. You can buy a laser pointer from any stationary shop or novelty shop.
Tip 2
Grey opal can turn black inside! Often when I'm looking at rough opal, I can tell whether it will turn black inside. The tell tail signs are in the natural breaks in the opal. When you have a parcel of opal from the same area or patch, you can usually find a small fragments (broken pieces) in it that will show you what body-tone it has inside the opal. Very often rough opal can have a grey outer skin that makes the opal look lighter than it really is. Inside the piece could be a different story. The potch can turn black and make the color-bar go dark as well. Making the opal black opal.
The benefit of doing this little test can be the difference between hundreds of dollars to thousand of dollars. Black opal is much more valuable than lighter opal and can reach prices of up to $15,000 per carat.
For more information on opal cutting or purchasing opal. Please email blackopalsdirect@live.com or you can call me on
Skype My username is Blackopaldirect and it's free!
Watch me explaining bodytone chart and the brightness scale.
This is only a guide to show you how the scales work.
Welcome back to Black Opal Direct!
This week I want to take you to the heart of the opal country. To see where the best opal ever came from. As some of you may know the Cooceran opal field has been the best supplier of black opal in the world. Through the 80s and 90s this place was a very busy mining field. Ad people from all over the world came to the Cooceran to try their luck in mining for the elusive black opal.
Many people came but only a select few made it in the opal world. You have to be lucky to find the big patch where opal falls out of the walls as you dig. This rare phenomenon still happens today to some people who have kept on going searching for the opal with a prospecting drill.
Once they find some opal trace or color in a 9 inch drill. It is time to bring the mining equipment and start digging.
Evaluating a rough opal color-bar so you can make the right decision.
I am showing you on a video how to change the sandpaper on your flat lap disc.
The tips and tricks will help you change that sand paper with the greatest of ease and I will also show you how to wear it down ready for opal cutting precious stones.
Sand paper is in my opinion one of the best ways to shape and dome your opal because it is inexpensive and easy to use. Soft Nova diamond impregnated wheels work well but cost so much more to work with.
So have a look at my video and let me know what you think?
Today's tip is a simple but effective tip that can save you time and the possible breakage of your opal.
When you have opal on your dop stick you can sometimes fins it really hard to take them off. So a little trick I use is put the opal on the dop stick in the freezer for 5 minutes then take them out and the opal will just fall off the wax. The contract under cold temperature making the opal fall of much easier.
Many people have been asking lots of different questions about the difference between. cutting opal with sand paper and using diamond impregnated soft wheels. So I have made a video on cutting and polishing an opal with Nova soft diamond wheels. There is a special technique I use that will give you a polish in half the time by a few simple steps as you will see the video below.
Opal is an organic shape and being organic it needs movement on the cutting wheel. Unlike faceting where the stone has to be still in order for the machine to do it's job.
See our most exciting day of finding the a great opal strike. It's not very often that opal comes spilling out of the agitator. But this time we were in luck. Have a look and see the amazing buzz that opal mining can give you.
See our most exciting day of finding the a great opal strike. It's not very often that opal comes spilling out of the agitator. But this time we were in luck. Have a look and see the amazing buzz that opal mining can give you.
See how I explain the differences between Nobby Opal and Seam Opal
I want to share with you the some secrets to carving opal with a dremel.
I will take you through the basics with my Father Jurgen. He will show you the different steps to carving a nice piece of opal. Plus listen carefully to the most important tip about making your own dremel bits.
See how I make a slice into an opal without making a mistake and then rubbing the opal to its approximate shape.
I have made a video as many of you have been asking what the best way to tumble opal is and over the years I have perfected the art - there are many people who live in Lightning Ridge who still can't get it right.
Please enjoy watching as I reveal some great tips and secrets to make your polishing a success.
