Featured Quick trip to Tiffany Co. with my finds!

I am lucky enough live near one of the nicest Tiffany stores I have ever been to. Their customer service is impeccable and they treat everyone so nicely..... as long as you have their jewelry and the authenticate it haha. Anyways took some of my finds from the past couple months over there for a complimentary cleaning and received some goodies as well. They do a magnificent job cleaning everything up! Take a look! Plus I highly recommend anyone do the same if you have any Tiffany jewelry! First find is a 925/ 18k gold ring, next is a vintage engine turned belt buckle, and lastly unfortunately is a ring that is just a tad too small argh! I must say their ring box is amazing!
Before:

 

Nice finds! I love the ring with the hematite cabochon.

 

WOW!!! They like to have their 'stuff' kept nice looking don't they!!!

 

All nice!
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Did you mean to state 'engraved' in regard to the buckle?

 

Engine turned is one of their signature belt buckle styles, they've had it for a long time. Not sure what engine turned means but that what it's called!

 

Hmmmm.....
I wonder if long ago grooving metal like that fell under that particular nomenclature but I've never heard it termed this.
This is what I know>

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I did find this too>
https://www.flickr.com/photos/the_justified_sinner/22849189764/

 

More like this, I think, King!
https://www.cnccookbook.com/rose-engines-the-preferred-machine-for-guilloche/

 

I done been learned something today!
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M-W states>

• Definition of engine turning

>a method of ornamentation of a surface (as of a watch) by means of a rose engine or lathe
>ornamentation in the form of a pattern of fine lines produced by engine turning