Lapidaryforum.net
General Category => Contests => Topic started by: hummingbirdstones on May 01, 2018, 08:23:48 AM
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Rules:
1) Cab must be made by you.
2) Cab must be made within the time period of this contest. Contest begins on the first of the month and ends on 11:59 p.m. on the last day of the month. NO pulling old cabs from your storage baskets!
3) As long as the basic shape is considered a cab it's golden. You can enter intarsias and carved top cabs such as cameos etc. After all, this is the OUTRAGEOUS cab contest! We love free form cabs! Pull out the stops and give us the best you have!
4) One entry per person please!
5) Please show photos of your slabs and preforms if you can so we can see your thought process and how you did things.
6) No finished jewelry pieces. Just the cab.
7) Cab sets are OK.
8) This is only for bragging rights and your cabochon photo posted up top in the forums unless someone posts a lapidary related prize and wants to ship it to the winner of the contest.
Let the games begin!!! :toothy10:
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It’s getting close to the end of the month and no entries yet, so I’ll lead off with a Welo opal from Ethiopia. I’ve cut many Australian opals but the Welo material is very different. That’s mainly because it’s hydrophane which means it absorbs water thirstily. And when it’s saturated the play of color disappears. Most of the time it returns within a few days as the opal dries out. But there’s also a danger it will craze after drying. Once it’s been wet and dried again there’s usually no crazing after subsequent wettings. This piece didn’t craze thankfully!
There’s also another problem I’ve run into. When it comes out of the mine it’s usually covered with what I think is volcanic ash that penetrates into the opal. The first image below shows the rough piece I started with after it was “skinned” of the ash. But sometimes the ash leaves fairly deep pits in the opal and removing them results in diminished yield in the finished stone. I forgot to weigh the rough but figure I got only about a 15-20% yield in the 2.29 ct. finished stone. That compares with a 20 to 25% average for Australian opal. My finished stone measures 9.4 x 13.4 x 4.9 mm. and even the video doesn’t really capture its brightness and vivid colors.
"Skinned" Rough
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Preform 1
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Preform 2
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https://vimeo.com/271553309 (https://vimeo.com/271553309)
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Nice job on the video! Glad it worked.
Gorgeous colors in that stone. They can be very beautiful when you get a good piece of rough that doesn't blow up on you and comes back clear after it's been wet. :icon_sunny:
Would you put a still photo up for the finished stone? Please and thank you! :icon_sunny:
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Thanks Robin. I'll try to get a decent still shot tomorrow, but you know how tough opal is to photograph.
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Well here is something i was playing with today. I don't know what the stone is, so at the moment I'm calling it "The Mystery Agate of Doom".
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I try not to procrastinate but.....
My entry this month is a piece of 55fossil's Deer Sky Jasper. I am going to his big sale tomorrow and will stock up on the good stuff!
51x32x5mm
Very low dome.
Tapered girdle.
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From a small sagenitic agate geode I had sliced a while back but just now got around to cabbing. This is old material, obtained about forty years ago. Not too sure what the material is called exactly and don't recall where it was from either! Maybe someone else knows?
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Yay, we have a contest! I won't be entering this month. I've been so busy I haven't even gone near my Genie. :sad5:
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Mearic71: your stone is a piece of Graveyard Point Plume Agate
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Thanks... thought it might be, wasn't sure.
Mike