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Subject:Jade grit/tool marks
Posted By: adam Tue, Oct 08, 2013 IP: 86.0.21.60

I have a copy of the British museums study of jade tool marks if anyone is interested? Just reply to this thread and I will send it to the email given in your title bar (as PDF file)

Subject:Re: Jade grit/tool marks
Posted By: ger Wed, Oct 09, 2013

yes would like it . thanks

Subject:Re: Jade grit/tool marks
Posted By: Jim Wed, Oct 09, 2013

This is very kind of you Adam. Thank you, Jim

Subject:Re: Jade grit/tool marks
Posted By: Steve G Wed, Oct 09, 2013

I'll take a look at it. Thanks.

Subject:Re: Jade grit/tool marks
Posted By: toan Thu, Oct 10, 2013

Thank you Peter
i WOULD BE GRATEFUL
Kind regards
toan

Subject:Re: Jade grit/tool marks
Posted By: willows Thu, Oct 10, 2013

I would like a copy. Thanks!

Subject:Re: Jade grit/tool marks
Posted By: Jo Thu, Oct 10, 2013

It will be much appreciated Adam.
Thank You
Jo

Subject:Re: Jade grit/tool marks
Posted By: robert claus Sun, Oct 13, 2013

I would appreciate receiving a copy.
Thank you.
Robert Claus2

Subject:Re: Jade grit/tool marks
Posted By: adam Wed, Oct 16, 2013

Here are the relevant pages (Sent to emails)...Excuse my late reply...Heads up to jade collectors...be prepared for some very rare and old jades to be sold next asia week at Christies (Not this November...Next May)

Subject:Re: Jade toolmarks
Posted By: Roger Fri, Oct 18, 2013

Adam:
Apparently you are confused by the reference to "tool marks" on jade carvings. The study by the British Museum only confirms the tools and methods used to carve jade prior to the 20th century and as desribed in nearly every jade study in the past 100 years.

When we refer to tool marks on a jade piece reputed to be 19th century or earlier, we are talking about the mark of POWER tools. Slippage is the most common mark by a power tool and almost impossible to make with the the old hand tools. The slow and tedious working with a hand tool required many hours of repeated strokes in the same path and could never create the slippage mark of a power tool.

Additionally, drilled holes and saw-marks made by power tools are quickly identified.

Subject:Re: Jade toolmarks
Posted By: Adam Sun, Oct 20, 2013

The british museum are well aware of the marks made by power tools (This was the initial point of the study)To differentiate between real and faked crystal and hardstone Persian seals... as the style has not changed for 2000 years plus...It was established that faked ones were easily identified this way...If you had actually read the full study you would see they had compared manual tools with electrically powered rotary tools as their first study.

Subject:Re: Jade grit/tool marks
Posted By: yuval jakobov Mon, Oct 21, 2013

hi,
i will be happy to get a copy of this study.
thank you very much
regards
yuval

Subject:Re: Jade grit/tool marks
Posted By: Super Tue, Oct 22, 2013

I must applaud Adam's willingness to share his "study of jade tool marks" article with others and the enthusiastic responses of many jade lovers to his offer. That speaks well of jade collection and jade collectors/lovers in this forum.

I do not know if the article that was offered by Adam is this article:

"The identification of carving techniques on Chinese jade
Margaret Sax, Nigel D Meeksa, Carol Michaelsonb, Andrew P Middletona"

http://www.sciencedirect.com/science/article/pii/S0305440304000421#

which was sponsored by the Department of Conservation and Scientific Research, British Museum. We had some discussions regarding it a while ago.

Ms. Sax also wrote another article:
"The technology of jades excavated at the Western Zhou, Jin Marquis cemetery, Tianma-Qucun, Beizhao, Shanxi province: recognition of tools and techniques"
http://www.sciencedirect.com/science/article/pii/S0305440312003950
which may be another interesting read.

Roger said,"The study by the British Museum only confirms the tools and methods used to carve jade prior to the 20th century and as desribed in nearly every jade study in the past 100 years.

When we refer to tool marks on a jade piece reputed to be 19th century or earlier, we are talking about the mark of POWER tools. Slippage is the most common mark by a power tool and almost impossible to make with the the old hand tools. The slow and tedious working with a hand tool required many hours of repeated strokes in the same path and could never create the slippage mark of a power tool."

I am not disagreeing with what he said (at least not yet until I can understand more regarding what he tried to say).

I would like to ask him to please clarify:
(1) What did he mean by "power tools? Powered by what, electricity, hand or foot? In what period in China were "power tools" being used in the "carving" of jades?

(2) What is his definition of hand tools and from what period in China only "hand tools" were being used in the "carving" of jades?

Please understand that I am not showing disrespect to his statements because I am a jade amateur myself and the more I learned about jade the more discouraged I had become because I found out there were a lot about jade that I still do not know and may never be able to really learn due to my limited resources.

This was what one forum member said about Sax's first article:

"Powered tools have been used for thousands of years.
A spinning motion is created in a number of ways,
With a bow and string that when moved back and forth spins the shaft on which the tool tip has been added., or foot powered wheels similar to a treadle which then rotated the tool.
Each of these tools leaves a signature in the jade. The article shows through the use Scanning
Electron microscope images, how to identify
each of these methods of carving. The illustarations are very clear."

and another:
"Professor S. Hansford said rotary tools used in wheet-cutting were not invented until the Iron Age because bronze is simply not hard enough to be used as rotary tools. However, tu (disc type) made of stone or other non-metal material were used during Neolithic time and Mr. Boda Yang did say rotary "powered" tool (or tool machine) were found during early Chinese dynasties (not powered by foot, but powered by hand). Therefore, it was indeed very difficult to understand tool marks or jade working tools that were available during archaic time. We must define exactly what "power tools", "rotary tools". "rotary tool machine" are before we can even discuss jade working techniques of tools."

Also,
"according to Prof. S Hansford, the quality of the working techniques shown on jade carvings, some time did not truly depend on the jade working tools or even truly reflect their true ages, but simply depend on the skills of the artisans. Therefore, holes drilled at Neolithic time by bamboo drill can be better than those made later with metal drills. On the other hand, some modern jade carvings, made with electrical high speed jade working tools can be made better in quality than those that were made at ancient time. For example, if you look at some of the Cu Da Ming (Ming dynasty carvings) jade carvings, that seem to be made very crude and poorly (they did not focus in details) but they would be indeed ancient Chinese jades."

Also, please remember that whether jade carvings were made with modern powered tools, ancient hand/foot powered tools or hand tools, very often you will not see any tool marks on them.

Therefore, while it will be helpful in learning more about tool marks, unfortunately using tool marks alone in the determining of the age of a jade carving can indeed be inconclusive.

Thanks in advance.

Super





Subject:Re: Jade grit/tool marks
Posted By: Roger Wed, Oct 23, 2013

Super:
Sorry, I should have spelled out high-speed power tools. I don't intend to enter into a long discussion similar to those that killed the old jade forum, but those of us who have collected jade for some time understand that "tool marks" generally refers to those marks produced by high-speed power tools. The tools and methods employed prior to the 20th century are basic to the study of jade.

As you know, high-speed power tools in the hands of a jade shop worker will produce far different results than in the hands of an artist. Prior to the introduction of high-speed power tools, we can assume that the artist made the first stokes of the design with great care and continued with slow and accurate strokes to develop the paths he would use to complete the piece. After the path was well set, the artist could then use a foot or hand powered tool at a controlled speed to avoid skipping or slippage from the path. Any slight deviation could be polished out without altering the design.

Since the development of high-speed power tools however, producing jade for the fake antique and souvenir market has become easier and faster, but the chances of high-speed tool marks are often overlooked in the interest of mass production.

According to one jade carver, the use of a high-speed power drill to make grooves is one of the most common causes of skipping (slippage). Holding the drill at a slant to make grooves, the bit often slips or skips on the hard jade surface. Instead of a careful hand polish, cheap pieces are tumbled or sand-blasted to smooth out rough edges, but skipping or slippage marks from high-speed power tools often remain in grooves and holes.


Subject:Re: Jade grit/tool marks
Posted By: LEE Fri, Nov 22, 2013

The modern jade carver can replicate a old carving to high accuracy with variable speed drills. they can go slow or fast. They can produce a satin polish or a gloss polish it is all very simple with modern machinery. Slippage can be avoided with various grit diamond burs driving it at a lower speed. spotting very fine drill marks typical of using a electric hand drill is what to spot. they than to run round diamond bur in the straight line cuts that we're cut by a disc in the past leaving a fine parallel machine marks that are perpendicular to the cut. the use of only drills and no string cut is the other sign of 20th century work. This can be found in reticulated areas. over rounded facial features and very smooth over polished carving edges is also a suspect. old cut marks like the hollow drill cut and the string cut marks are good signs.

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Subject:Re: Jade grit/tool marks
Posted By: adam Wed, Oct 23, 2013

Well said super...
Although it may be true the small disks used in electric tools 20+ years ago often left slippage/chatter marks (That any faker worth his salt would remove)the grit infused bullet shaped points used nowadays do not leave chatter marks....Due to this, the "Chatter marks" were only ever useful in identifying fakes of the lowest quality!!

Subject:Re: Jade grit/tool marks
Posted By: adam Wed, Oct 23, 2013

Further to the above reply...People interested this topic should seek out a british documentary about the famous "Crystal skull of doom" in this documentary the microscopic fine grit abrasions used in the polish were shown to prove it was a modern fake made with electrically powered tools...

Subject:Re: Jade grit/tool marks
Posted By: Gigi Mon, Nov 18, 2013

yes please!

Subject:Re: Jade grit/tool marks
Posted By: thierry bogaert Mon, Jan 27, 2014

Hi, Can you send me a copy of the British museum study on tool marks on ancient jade? Mostmappreciated.
Kind regards, Thierry

Subject:[email protected]
Posted By: Cordelia Tue, Jan 13, 2015

Hi Adam.I can see this is an old thread but can you send it to me please? Thank you!

Subject:Re: Jade grit/tool marks
Posted By: John MacWhinnie Tue, Mar 17, 2020

Yes, I would love to have a copy of the British Museum study, Thankk you very much.


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