Lapidary thread

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Re: Lapidary thread

Postby Lefty » 12 Mar 2014, 21:33

The stone as it was originally on the dop, except for the little facets I put around the top just phukking around.

Image


An unclear shot of the finished pavillion. You can see I've squared the stone off - the preform was round - obviously in preparation for a brilliant cut or something similar - but I squared it so I could do a very much simpler style of cut as a first attempt.

Image


The machine itself. A fairly simple set up, though capable of a very high degree of accuracy.

Image
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Re: Lapidary thread

Postby HBS Guy » 12 Mar 2014, 22:13

Hmm what sort of crystal structure on that original stone? Octagonal?
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Re: Lapidary thread

Postby Lefty » 12 Mar 2014, 22:19

HBS Guy wrote:Hmm what sort of crystal structure on that original stone? Octagonal?


Impossible to say - it was already ground to shape. It looks like topaz and also displays a number of that minerals attributes. It's a stone commonly faceted here in Australia.
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Re: Lapidary thread

Postby HBS Guy » 12 Mar 2014, 22:32

You need a copy of Dana’s Manual of Mineralogy. Have a look online.
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Re: Lapidary thread

Postby Lefty » 12 Mar 2014, 22:56

Will check it out. But better turn in now - night JM.
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Re: Lapidary thread

Postby HBS Guy » 12 Mar 2014, 23:19

Niters Lefty.
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Re: Lapidary thread

Postby Lefty » 16 Mar 2014, 19:33

Greg says you can stilll get spare parts for that little machine and it's the exact same make and model that he learned to cut on.

Dad gave me some more faceting material - clear quartz, smokey quartz and labradorite :jump
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Re: Lapidary thread

Postby HBS Guy » 16 Mar 2014, 19:50

leave the labradorite till last I reckon—more valuable than quartz.
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Re: Lapidary thread

Postby Lefty » 16 Mar 2014, 19:57

HBS Guy wrote:leave the labradorite till last I reckon—more valuable than quartz.


Oh yeah, I intend to make my beginners mistakes on cheap stuff :jump The labradorite is from Springsure, only about 40 minutes drive from the field. Looks a bit different to a lot of the overseas stuff - it's clear, sort of pale honey-coloured .
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Re: Lapidary thread

Postby Lefty » 16 Mar 2014, 20:37

The labradorite - should be some good faceting pieces here....once I get more proficient.

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Re: Lapidary thread

Postby Lefty » 18 Mar 2014, 17:47

That window I cut on that piece revealed that the nice orange material was only a thin layer on the outside and the inside was a dissapointing pale whitish-yellow :sad

But I do have a couple of small pieces where you can clearly see the whole stone is orange all the way through. Hopefully I get some decent fully orange/red stuff this weekend. There's lots of chert and petrified wood pieces to be found in the same spot - obviously some ground nearby was heavily saturated in silicon in solution.
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Re: Lapidary thread

Postby HBS Guy » 18 Mar 2014, 18:57

Excellent.
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Re: Lapidary thread

Postby Lefty » 04 Apr 2014, 21:36

Just got back from the lapidary club. They've got a pretty good set up in there. Faceting, cabbing, tumbling, jewellery making - the whole kit and kaboodle pretty much. Looking at their faceting machines, you can really see just how advanced they have become and how ultra, ultra basic mine is in comparison - mine looks like a fucking toy alongside these things :bgrin . Vic will teach me to cut, gotta wait a few weeks since he has to have an operation on his hand. In the meantime, the young bloke and I are gonna jump into cabbing. Could have started tonight but we were both wearing thongs and the rules are that you must be wearing closed-in shoes.

They were very impressed with that orange chalcedony - didn't take any with me but the treasurer had seen the pics I posted and asked if I could bring some in. Think I might make a piece of that my first cab :jump

Only $30 for a year's membership, seems pretty good.
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Re: Lapidary thread

Postby HBS Guy » 05 Apr 2014, 02:22

Yeah, good value and a fun thing to do.

Ehehehehehe have to wear closed in shoes at dog club too—in case you tread in some dog poo :jump
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Re: Lapidary thread

Postby Lefty » 05 Apr 2014, 09:37

At least you can't lose a toe to that like you can to a sharp cutting tool :bgrin
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Re: Lapidary thread

Postby Lefty » 11 Apr 2014, 23:34

Just got back from my first night at the lapidary club. Polished my first half-thunderegg and started my first cab :jump Not chalcedony, they gave me a piece of petrified wood.

Thunderegg was already sawn in half. You start work on the flat lap, a machine a lot like a gem cutting lap but much larger and without the arm and wheel for setting angles. The lap is a steel wheel about half a metre in diameter, uncharged with diamond unlike the gem cutting laps which are impregnated with various grades of diamond. You apply silicon carbide grit, 80 then wash down the wheel, 220 and wash, 400 and wash, 600 and wash, each time marking a grid pattern on the face of the stone with an aluminium pencil, once the grid is completely gone the face is pretty flat - then move to another flat lap made of what looks like carpet and apply tin oxide for the final polish. They came up good, quite interesting.

They used a stencil to mark oval pieces out of a slab of petrified wood. This was the beginning of the cab. A club member cut it roughly to shape on the trim saw (a small rock saw) and we ground it to the perfect oval shape on 100 and 220 grit diamond bench grinders. The ovals were dopped on pieces of timber dowel rod - and that's as far as I got before time ran out. Will finish it the week after next since I'll (hopefully) be at the field. Young bloke will be going in next Wednesday to finish his.

One of the blokes there is a qualified gemologist so I took him some of that clear stuff I found at the Hartz range to show him. He took one look and said "well it's definately not quartz". Music to my ears :jump He pointed out that this stuff has strong, near perfect cleavage while quartz has a very much rougher, indistinct cleavage. He suspects possibly goshenite but isn't sure and has taken a bit home with him to test with his identification equipment.

I could really get into this :yellow :purple
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Re: Lapidary thread

Postby HBS Guy » 11 Apr 2014, 23:42

Sounds really fascinating!

Goshenite—what a name. Did someone find a specimen of it and go “gosh” hence goshemite?

Hmmm—a type of emerald! http://www.gemselect.com/other-info/goshenite-gems.php
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Re: Lapidary thread

Postby Lefty » 11 Apr 2014, 23:47

Apparently first discovered near a town named Goshen in the US.

Yep, it is a kind of emerald/beryl - unfortunately as far as value goes, it's the poor cousin of the much more valuable varieties of beryl such as emerald and aquamarine. But it would still look great faceted :jump
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Re: Lapidary thread

Postby HBS Guy » 11 Apr 2014, 23:57

Hehehehe well if it was real emerald you wouldn’t dare work on it—or be allowed to :roll :bgrin
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Re: Lapidary thread

Postby Lefty » 12 Apr 2014, 09:36

HBS Guy wrote:Hehehehe well if it was real emerald you wouldn’t dare work on it—or be allowed to :roll :bgrin


If I was going to do it, it would be getting put away for probably a couple of years while I spent all that time learning on material that I didn't care about phukking up :jump

Hmm, an interesting thing about goshenite was that larger pieces were once ground into lenses for eyeglasses because of it's extreme clarity.
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Re: Lapidary thread

Postby HBS Guy » 12 Apr 2014, 10:23

So some people really did have rocks in their head? :bgrin
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Re: Lapidary thread

Postby Lefty » 12 Apr 2014, 19:11

HBS Guy wrote:So some people really did have rocks in their head? :bgrin


For sure......

http://thumbs.dreamstime.com/z/skeleton-x-ray-rocks-his-head-7902942.jpg

Oh wait, that's an x-ray of Abbot's head :jump
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Re: Lapidary thread

Postby HBS Guy » 12 Apr 2014, 19:33

:bgrin
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Re: Lapidary thread

Postby Lefty » 02 May 2014, 16:31

Heading back into the club tonight for the first time in a month since joining - two Fridays were public holidays and the other I was out at the claim. Young bloke is already ahead of me, having finished his first cab (wife took him in while I was out at there). Might take a bit of that chalcedony in and see if it can be run through the trim saw and a small cab made out of it. Also need to find out if the resident gemmologist found out exactly what that clear material I found at Hartz range is.
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Re: Lapidary thread

Postby Lefty » 02 May 2014, 18:59

Ok, heading in to the club. Won't be home till late tomorrow, heading out to Emerald early in the morning for that pulsator. Catch you tomorrow night, hopefully with some pics :jump
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