Cyclops Contact Lens...

[mohs]

mohs want to know

[mohs]

I took the lens to couple experts in the field
A retailer in rock
Specializes in mass produced Brazilian agates


The retailer says that its unique and NO
They never seen that design on the mass market

The local rock hound confirms it’s a real agate
And real nice one at that that
Baffled to …to how its done

Besides some automated, 5 axis, CNC, 500,000 dollar machine

And then its just end up floating around at rock bottom!

Maybe its ancient ?
Like crystal skulls….

[mohs]

Mar 7, 2018 16:35:17 GMT -5 NRG said:

The telescope makers make concave curves as normal business. They use a flat grinder and grit to make the inside curved. Its done painstakingly by hand the and result is a mirror with exquisite optical quality.

www.bbastrodesigns.com/JoyOfMirrorMaking/RoughGrinding.html

ya know Scott
they do a lot of the lens grinding at the UofA Tucson
that may be worth a trip
I think those guys would find this interesting...

[gemfeller]

mohs , you seem obsessed with finding out how the bowl was cut. Go the library and hunt up a copy of John Sinkankas's book "Gem Cutting: A Lapidary's Manual." I have the second edition. In mine on pages 218-19 the procedure is discussed and illustrated, along with a sketch of a simple machine for grinding, sanding and polishing the concave interior. You could probably build one for 200 bucks or so.

It's an old book and new methods would make it somewhat simpler. By ganging up a bunch of diamond saw blades of the desired radius it might be easier to rough out the interior of the bowl freehand after initial sawing and chipping out the interior "slices" as shown in the book. In any event the process is fairly straightforward though time consuming.

Cutting the convex exterior would be accomplished in much the same way as preforming a rough piece for a sphere plus a lot of laborious hand-grinding etc. Happy cutting!

[mohs]

Thanks Rick !


can visualize the machine-- the process

what blows me away is that it made of agate
so hard- so smooth- no dips- no scratch marks-
basically-- 7/64th of inch thick
all away around

so lots tedious abrasive action

a softer stone much more doable

yes I am obsessed

mohs

[mohs]

It had to start a solid geode or thunder egg
Cut in half or less
Using the heel as the convex

The reason I assume that
is because of the rough left on the rim
that would have been ground away
if it had been ground as a sphere first

I assume you would hog out, smooth,
and polish the concave first,,,mostly ?

Then finish grind & polish the convex
the back of stone

This would help to maintain the gauge of the thickness


The druzy at the bottom is really unique
--sure it was planned that way
yet
The person must have been concerned
with all the labor
was it going to crack?

Definitely knew their agates…

[mohs]

the other method
is to grind a sphere first
Slice off a part of that
and start the process….


Thanks guys !
I got it now
mostly

[mohs]

[Fossilman]

How ever it was made..Mad made or natural,its pretty damn cool......

[zarguy]

3 stackable agate bowls on eBay:

www.ebay.com/itm/LOT-OF-3-Polished-STACKABLE-Bowls-ASHTRAYS-Agate-Stone-Rocks-/282868229025

Lynn

[mohs]

wow zarguy
that blow up my lens
hhhmmm...

and only 30 dollars
at that sort of money
I'm not sure why there not more popular

that why went to the retailer
I had nagging feeling that they may be common

again it remarkable

thanks for posting!

[mohs]

the question becomes


how can it sale on the market for so inexpensively?

[zarguy]

mohs - Brazilian agate is very abundant.
It comes in small to large nodules.
Some of it is bland until they heat treat it to bring out some contrast.
And then there are the BRIGHT PINK & BLUE slabs, wind chimes, bookends, clocks, etc.
Don't you just LOVE the colors of nature?
Lynn

[mohs]

Thanks Zar!

[pauls]

The cutter is a hemispherical diamond blade.

Simple machine, simple process and probably as quick as cutting a slab of Agate.

[zarguy]

Don't throw out your blade if it gets dished!
Or did I mean bowled?
Lynn

[Jugglerguy]

Mar 9, 2018 15:13:48 GMT -5 pauls said:

The cutter is a hemispherical diamond blade.

Simple machine, simple process and probably as quick as cutting a slab of Agate.

Do you have pictures or videos of the machine?

[pauls]

Mar 9, 2018 17:13:09 GMT -5 Jugglerguy said:

Mar 9, 2018 15:13:48 GMT -5 pauls said:

The cutter is a hemispherical diamond blade.

Simple machine, simple process and probably as quick as cutting a slab of Agate.

Do you have pictures or videos of the machine?

Not any more, I used to have a picture many moons ago, it went west when a past computer hard drive died. The picture was from a 1970s Lapidary Magazine from memory.

I have tried searching but didn't find anything other than a page for a factory in India making the bowls, lots of pictures of nice rock bowls but not of the process.