Post by ejs on Jan 17, 2009 16:34:36 GMT -5
Greetings. Along with the black jasper that I posted about yesterday, I tumbled some Noreena jasper in the same batch. I combined the two because I thought the color contrast would be interesting. The Noreena is some of the most beautiful material I've ever worked with, so I was really excited to see the results. I took a long time with the process to maximize the final product. I will admit that I am a bit disappointed with the results, but I suspect that may be due at least in part to the material rather than my method.
I started with two chunks of Noreena purchased from Riverbend Lapidary (for $6/lb.). Here is what one of the chunks looked like at the start:
pic1:
I broke it up this summer using a hammer. You can see the nice patterns of red/yellow/grey:
pic2:
pic3:
I ran it through my usual regimen of multiple 5-day rounds of 60/90 SC coarse. I ran some of it in a Lortone 6 lb. and some in a Lortone 3 lb. I ran it for a total of 8 rounds, but no stone ran for more than 5 or 6. I prefer my rocks to be very rounded, so that took a while. Here is how it looked coming out of the coarse (shown wet):
pic4:
I then ran it through a 7 day 120/200 SC medium tumble. Here is how it looked after that (again, shown wet):
pic5:
pic6:
At this point, I was so excited, I could hardly wait to see how they came out. I was anticipating my best tumble ever. I ran them through 10 days of 500 SC (with lots of pellets to cushion from here on out), then 10 days of 1000 AO, then 14 days of cerium oxide polish (figuring that CO was the best for a hard jasper like this), and then a final burnish with Borax for a few hours. Here is how they came out shown dry (keeping in mind that I am not a very good rock photographer):
pic7:
pic8:
pic9:
I love the colored swirls and patterns in this rock. Here are some close ups:
pic10:
pic11:
pic12:
But I can't help but feel a bit disappointed. It's a good tumble, but not as nice as I'd hoped. I think there are two issues. First, there was some cracking in the later stages. I don't think this was due to undercushioning as I had a large amount of plastic pellets in the last 4 stages (different pellets for each stage). I figure that either the black jasper that I tumbled it with is harder than the Noreena and fractured it, or that I messed up the ratio of water/rock in some stage in a way that caused too much contact. It's also possible that I produced fractures when banging up the rock. Next time I'll try cutting it on the WF wet tile saw to avoid that problem. The other problem is that they didn't take a great shine. Contrast the Noreena to the black in this photo:
The black and the Noreena were tumbled together. Obviously, the black took on an amazing shine, but the Noreena didn't. This makes me suspect that Noreena just does not lend itself to a high-gloss shine, but rather a matte finish, like some picture jaspers. So I don't blame myself for the lack of shine. I am currently running another batch of black/Noreena, so in about 6 weeks I'll have another batch to compare. I may combine the Noreena from the two batches and run them through a week of AO polish to see if that produces better results.
So, I'm happy to have a bunch of smooth, interesting and pretty stones, but I was hoping for better. And and all suggestions on how to improve this batch are welcome! Has anyone else tumbled Noreena? Did you get a high-gloss shine? Sorry I rambled for so long! Thanks for looking.
I started with two chunks of Noreena purchased from Riverbend Lapidary (for $6/lb.). Here is what one of the chunks looked like at the start:
pic1:
I broke it up this summer using a hammer. You can see the nice patterns of red/yellow/grey:
pic2:
pic3:
I ran it through my usual regimen of multiple 5-day rounds of 60/90 SC coarse. I ran some of it in a Lortone 6 lb. and some in a Lortone 3 lb. I ran it for a total of 8 rounds, but no stone ran for more than 5 or 6. I prefer my rocks to be very rounded, so that took a while. Here is how it looked coming out of the coarse (shown wet):
pic4:
I then ran it through a 7 day 120/200 SC medium tumble. Here is how it looked after that (again, shown wet):
pic5:
pic6:
At this point, I was so excited, I could hardly wait to see how they came out. I was anticipating my best tumble ever. I ran them through 10 days of 500 SC (with lots of pellets to cushion from here on out), then 10 days of 1000 AO, then 14 days of cerium oxide polish (figuring that CO was the best for a hard jasper like this), and then a final burnish with Borax for a few hours. Here is how they came out shown dry (keeping in mind that I am not a very good rock photographer):
pic7:
pic8:
pic9:
I love the colored swirls and patterns in this rock. Here are some close ups:
pic10:
pic11:
pic12:
But I can't help but feel a bit disappointed. It's a good tumble, but not as nice as I'd hoped. I think there are two issues. First, there was some cracking in the later stages. I don't think this was due to undercushioning as I had a large amount of plastic pellets in the last 4 stages (different pellets for each stage). I figure that either the black jasper that I tumbled it with is harder than the Noreena and fractured it, or that I messed up the ratio of water/rock in some stage in a way that caused too much contact. It's also possible that I produced fractures when banging up the rock. Next time I'll try cutting it on the WF wet tile saw to avoid that problem. The other problem is that they didn't take a great shine. Contrast the Noreena to the black in this photo:
The black and the Noreena were tumbled together. Obviously, the black took on an amazing shine, but the Noreena didn't. This makes me suspect that Noreena just does not lend itself to a high-gloss shine, but rather a matte finish, like some picture jaspers. So I don't blame myself for the lack of shine. I am currently running another batch of black/Noreena, so in about 6 weeks I'll have another batch to compare. I may combine the Noreena from the two batches and run them through a week of AO polish to see if that produces better results.
So, I'm happy to have a bunch of smooth, interesting and pretty stones, but I was hoping for better. And and all suggestions on how to improve this batch are welcome! Has anyone else tumbled Noreena? Did you get a high-gloss shine? Sorry I rambled for so long! Thanks for looking.
