Experiment - cabbed a garnet

Can't facet yet so I thought I'd see how one of those almandine garnets would cab up. I'm spewing now that I treated it as an experiment and didn't take more care - I see no reason why it wouldn't look good in a ring.

Except that the shape is slightly out, the polish could have been a little higher and there is an unfinished bit near the girdle - all because I treated it as a muck around.

Next time I will take it seriously.

Nice mate

Looks really good mate,I might try doing one of my stash one day when I've had more practice.

Cheers guys.

I araldited it to a screw as a dop stick - something so small and fiddly compared to anything else I've cabbed, it seemed epoxy or superglue would be easier than wax.

Skipped the first grinding wheels and started shaping on the #360 diamond. That was the right thing, the stuff seems reasonably hard but with the small size of the stone, the heavier wheels would have destroyed it with one slip. Moved to wet/dry and it seemed to do a reasonable job. But they only had them up to #600 at the club.

Brought it home, went #800 then #1200 wet/dry and then a well-worn #2000 diamond paper disc. Pre-polished it ok. Wasn't sure how to approach polishing but remembered that almandine garnet is iron aluminium silicate and tin oxide is supposed to be particularly effective on silica-based things. It certainly puts a brilliant polish on agate. The tin oxide buffed it up not too badly.

Did the same with a piece of black spinel. It was noticably harder then the garnet. It failed to respond to the tin oxide, taking on only a dull shine. I guess diamond is probably the polish for such a stone.

Not bad!
It looks much better than my trial on a sapphire (bomb crystal with an octogonal shape, wondered if it could be a star, but cracks are ruining it)

Looks impressive to me Lefty, mounted on a silver ring or pendant and it would look very impressive.

Thanks for sharing the screw dopstick idea.

I've seen some garnets from the same place facetted and they look really nice but the majority tend to be fairly dark, as was this one.

I was surprised how much light gets inside this one even without backlighting - the dome of the circular cab obviously acts like a lens, bending the light even if there are no flat facets to reflect (except the bottom of the cab). As Wally suggests, I'm now picturing them as high-domed cabs set in silver rings or pendants.

I reckon the darker ones might look good as double-sided cabs set in drop earrings so that the light can enter them from both directions

Very nice little cab Lefty, good colour too.

Re your spinel problems, could be you are creating subsurface issues with the grade of your cutting laps. Depending on the amount of rough to take off I would start with 600, 1200 then 3000.

I have had good polish results on spinel with cerium oxide (which I actually mainly use for opal)
For cabs, ie opal and other freeform stones, I use a flat leather lap, medium speed with the compound applied by a small spray bottle. Very light touch and don't let the stone get hot.
mike

Thanks Mike.

I have papers at home up to 2000, I'll return it to the 600 or 800 and work up and see how it goes. I'm still using paper discs on laps I cut from high-density foam rubber on an old Hall junior faceting machine but I'm shortly buying a cabbing machine. The one I was looking at is a Cabking 6V3, a 6-wheel set up with 80 and 220 metal bonded diamond grinding wheels and 280, 600, 1200 and 3000 resin bonded diamond wheels. Do you know anything - good or bad - about this machine? I've heard that the brand new resin bonded wheels can have a tendency to leave deep scratches until they have been well worn in, especially above 3000.

That looks great Lefty, for some reason I prefer a nice cabbed stone over a faceted one, they look like a pool of colour with no harsh edges.

Heatho.
In my very humble opinion nothing compares to a gold, star sapphire cabochon.
In a facetted stone, the fire from a light coloured zircon pretty much equals that of a diamond.
But I still prefer the cab.
mike