3 years, 2 months ago-
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Hey all,
I am having a heck of a time getting the fine scratches out of Aquamarine and golden Beryl. I have a battlap and a Darkside for polishing. Any ideas would be greatly appreciated. Thanks for the help and have a great day!!
EdEd,
Cerium oxide and chromium oxide are both good polishes for beryl. Although, if you are using powder chromium oxide it will find its way into the pours of your stone, leaving it green.
My polish of choice for beryl is cerium oxide. There are a few places where you can get cerium laps as well as two different grades of cerium. LightningLap.com sells cerium laps as toppers that use the white cerium (99%). These cost around $30.00 and they work exceptionally well.
Pol-A-Gem sells standard size red cerium laps (94%) that also work quite well.
The difference between red and white cerium is that the red is a bit more coarse. But as far as polishing is concerned the finish they leave is like the difference between 100,000 and 200,000 diamond, which is very slight and only noticeable under magnification.
Gearloose sells the Greenway lap which is green in color and uses chromium. I have not tried to use it on anything but green stones, so I don’t know if it leaves any green residue on the stone.
You can also get a combo pack of ultra laps that have cerium, aluminum, chromium and tin oxide. They work well but leave a slightly rounded meet.
If you choose to use the white cerium laps there is another suggestion that I have. Covington sells a cerium spray kit which includes a spray bottle and some white cerium powder. You put a measured amount of cerium powder in the bottle, add water and shake before spraying it on your polishing lap. Gearloose also sells red cerium batsticks which work well with darkside and battlaps.
Tom Mitchell
The Greenway is excellent on beryls, and leaves no residue. People who can afford emerald seem to like it because it doesn’t collect in the cracks 🙂
Some people have reported good results from the Creamway (zirconium oxide), but it really shines on quartz (pun intended).Thank you both for the responses. I had great luck with both ideas! Can’t tell you how much I appreciate your time!!
Ed
again i repeat the easiest way to polish is tin and diamond and works on all stones. we cut at fast speeds and use a 1200 metal bond(plated) diamond wheel for final, before polish. now when polishing we go VERY slow on a tin lap made by whomever and DEFINITELY NOT scored in any way. run slow with VERY low drip of water, no oil or paste, and just a finger tip touch of powder on the working area of lap to make a mud/slur will give a perfect polish. i/we use a good grade of 50,000 grit powder. i buy it on ebay from china at $80 for 1000 carats, 8 cents a ct., and lasts for a very long time many stones by several cutters. the diamond at this slow speed tends to charge the tin lap. using so little water doesn’t wash of the diamond just the cuttings off, even at 50,000 your cutting.. scoring leaves chanals for cutting to build up in and dry out causing build up scratching, even dried polish can scratch. and flooding with water just washes the polishing agent off the lap. gemmakermz@cs.com
since my last posting at bottom of this page i had others contact me on my way of polishing. i’ve had to tell some to clean their tin alloy lap and with a alcohol too. then follow my method and they are now very happy polishing all stones that way, even the old timers. contact me for an questions, i’ve only been doing this for 50 yrs and now have a 13 yr old junior club member faceting and written up in the September 2019 rock and gem magazine. i teach faceting to all ages for free.
I prefer chrome oxide for my beryls, of any color. Some folks (like several cabbers in my guild) like using diamond for everything, and I understand the appeal of that approach–it’s simple. I still prefer oxides whenever possible, and diamond only on hard stuff (Mohs-wise, like corundum, CZ, and up) or on problem materials. To me at least, the oxides work quicker and have more pop.
I’ll add another vote for the CeOx Lightning Lap for Beryl, or just about anything Mohs 8 or below.
I’ve also had success using a Darkside charged with a CeOx slurry.
(Easy on the water drip.)
I love my Lightning Lap Cerium Oxide. Pops that Quartz, nice to know about the Beryl and 8 mho’s and lower when to use. Thanks guys. Can’t wait to cut my first $3.2k ct stone, lol. So I take it that this polish method works on the man made lab materials too? And what works best on spinal?
In my experience at least (which isn’t more than about a decade), all the lab materials polish like their natural counterparts–that’s partly why I teach on synth garnet (YAG/GGG). If anything, the synthetics are more predictable and it’s the naturals you have to worry about–for example, directional hardness in natural sapphire.
Matrix and cerium is the best and quickest I have found. On a 12mm stone it takes approximately minute and half for table and 15 seconds for each facet at medium slow speed. I use the red cerium. Good enough for the opal cutters in Australia.
Just want to add to the above statement that this is going directly from a 600 grit lap, no prepolish.
one of my students just won an award for faceting in tuscon and she uses diamond on tin, 13 yr old nadine, and yes eric i too like to use yag for the first stone they cut. have some laser yag— neodymium yttrium aluminum garnet from a maker here in washington and a special reverse brilliant cut that i put them through. takes about 3-5 hrs and they finish going home with an extremely flashy stone and all have polished on a TIN lap with 50,000 that works on all hardness stones. i just polished 80 facets and table. facets took less than 10 min. and table 15.
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