How to cut and polish Opals?
Rough opal comes directly from the mines. They are uncut and unshaped gemstones, which are sold after cleaning, to either opal cutters who are using them for a hobby, or for serious professional cutters who on-sell the completed stones to jewelers and opal manufacturers.
Australian opal mines are the source of most of the world’s production of opals, being over 90% of the supplies. Opal rough can come in all colors and shades. Broadly speaking, white and crystal opal rough comes from the Coober Pedy fields in South Australia, black opal comes from Lightning Ridge in NSW, and boulder opal comes from Queensland.
This article will teach you how to cut solid opals to produce the best results. Firstly, a few hints. Pay attention to detail. Follow step by step to reach perfection!
List of equipment you will need to cut the opals are Dop sticks
- Dop wax or strong glue
- Trim saw with thin
- Blade (with rim thickness approximately 0.02”)
- Diamond grinding wheels 80, 220, 600, 1200, and 3000 grits
- Cutting equipment
- Rough leather
- Polishing disk
- Tin oxide polish
- Lamp with the 100-watt bulb
- Safety glasses
- Dust mask
- Old work clothes
- Water supply
Here are the step by step process to cut and polish the opals
Step 1. Firstly, pick up opals and saw it up
Most of the rough material you will buy has already been slabbed up so you can clearly see the Opal layer. If the material is completely rough and you cannot easily see the Opal you will need to saw the stone to expose the Opal layer.
When Opal occurs in ironstone, it has flat and straight parallel lines along with the matrix. There is a better chance that the opal will track this line. If the rough is soaked in water let it dry first so you can see where the Opal is running. Check for cracks running across the stone and again look for any imperfections throughout the stone. If there are cracks running through the stone you can use the saw to split the opal down the crack. This will avoid any problems later on.
The saw blade should always be underwater. Use plenty of water to keep the dust down and the Opal cool. Never cut dry as opal will heat quickly and crack.
Step 2. Use the coarse cutting wheel to remove a material
Use the coarse grit wheel to remove material quickly. A combination of 80 and 220 grit wheels can make rubbing down the Opal much easier. Try not to get too close to the line of opal. The layer of opal can be unpredictable so try and stay just above the layer.
Now decide which surface is going to be the top. Base your judgment on the form and layer of the opal, the coloring, brightness, and width of the surrounding material. Try to make sure that the material directly below the Opal is as dark as possible. This dark setting will create the colors of the opal to stand out. If there is a thin cover of dark potch between the row of Opal and the ironstone it will make the stone pop. You must try to cut the stone so that this black coating will give the backdrop for your stone.
Step 3. Rub away the Ironstone
Now that you know which way the opal will face using the 220 and 280 grit wheel. You must not come into contact with the opal once you decided to use the 220-grit wheel as it can rapidly eliminate quite a bit of the vibrant materials.
It is also advisable to use light pressure ranging from the 220-grit wheel as you get closer to the opal. You must keep on eliminating ironstone until you are just about to display opal in one part of the surface. Occasionally, before you reach the opal, you will even notice that the color of the ironstone will change.
Switch over to the 600-grit wheel in order to expose some opal. At this period, you are not trying to eliminate all of the ironstones from the surface. You can do it by going back and forth between the 600-grit wheel with medium pressure. Use light pressure on the 280-grit wheel. Once you establish how the layer of opal operates, you can stop working on the top.
Step 4. Dop the Opal
First, we need to get the stone onto a dop stick. When the stone is on the dop stick it is easier to maneuver and shape. Use the 220-grit wheel and flatten its reverse side-tone. The two most common ways to dop an opal is with Glue or using wax.
a) Glue: The base of the stone must clean and dry. Apply one or two drops of glue to the dop sticks. Pre-heat the opal by resting it on the border of the dop pot for not more than 30 seconds. Use light pressure to push the opal into the dop stick. The glue will dry after about 30 minutes.
b) Wax: If the reverse side of the opal is spongy and the glue does not work you may use wax as an alternative. Heat the Opal and drop melted wax onto the opal before applying it to the dop sticks. You must make sure the dop sticks have a sufficient amount of melted wax on them.
Step 5. Forming the proper shape of the opal
At this point, you are required to make some significant decisions. Look at the general appearance of your stone, both the ironstone and opal. Their combination can be relatively beautiful.
Keep on eliminating ironstone with the 600-grit wheel. Think about keeping the stone moving. The 600-grit wheel can still reduce opal and create smooth spots and scrapes. You can do a lot of things during this stage of cutting. You are eliminating scratches from previous stages.
Then, eliminating ironstone from the surface, and building the surface and form of the stone is pleasing to the eye. Check your stone and observe what it shows you. You might require going back to the 280-grit wheel and changing its form. Once you have eliminated the big scratches and are pleased with the look, go to the 1200-grit wheel.
Step 6. Finalize the shape and expose the opal
In this step, the 1200-grit wheel will eliminate almost all noticeable scratches. It will not do much to modify the form of your stone, but it can better its form. Use reasonable pressure and make sure the stone is continually moving.
Stop regularly and clean up your stone to verify the progress and ensure that the scratches are completely vanishing.
Once you have removed the noticeable scratches, shift to the 3000-grit wheel, or if you’re not using a 3000-grit wheel, begin to clean your stone. If your device consists of a 14,000-grit wheel, it is advisable not to cut boulder opal. This wheel begins often with scratches.
Step 7. Final polish
The next phase is the process of polishing. In order to make it shine, you can use tin oxide for cleaning the foam-backed rough leather pad. Just lightly soaked it with water through the use of a spray bottle and with the running device running and spinning pad.
Also, use a brush to apply a well-stirred combination of water and tin oxide onto the moist pad. From here, the water mixture as well as, the tin oxide must be thin enough so that it does not clomp, and has the uniformity of thin gravy.
Just keep the opals stirring by turning the dop stick between your fingers and by varying the position of the pad. Do not allow the opal to get too hot. Sometimes, the coarse leather pad can seize your stone and pull it out of your hands. This is usually because the pad has dried out or if the stone has a rough surface or even pointed edges.
Step 8. Finish the back of the stone
Lastly, you can do the finishing of the back. When you have completed polishing takes the stone from its dop stick. You can use light to a standard pressure for roughly about 220-280 for your grit wheel in order to take out any residue of the doping matter.
You must keep the stone flat against the wheel, but turn it slightly so that scratches will be avoided on its back. At this point, select what you prefer for the specific size of the stone. When you arrived with the suitable thickness, apply the 220 or 280-grit for the wheel that can help to minimize chipping when setting.
You can either think the opal completed, or get a more finished look by taking the back through the remaining chain of finer wheels. You must cut the back portion of stones by means of 1200 or 3000-grit wheels.
Step 9. The final outcome
After all of the opals have been cut and polished they can be sorted and graded. Opals make great pendants. All that is needed is a drill press to create a hole in the tip of them. Thread through a leather strap and you have yourself a beautiful Opal necklace.
A handy tip from an opal cutter: Worried about turning your machine on and off with wet hands? Try and glue a dop stick to the power board switch. That way nothing wet ever comes in contact with electricity.
Limanty provides the beginner rough 5 Opals for the cut and polishing process. Have a great time in experimenting and learning the new techniques on opals cutting and polishing here https://limanty.com/collections/opals/products/begginner-5-rough-opal