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Question about miscellaneous holes drilled in Chinese carved beads
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Posted by: jrj Post Reply
09/05/2019, 19:50:52

I have been wondering why there are random-seeming holes in some types of carved Chinese beads that are not terribly old: see the example below. Do they serve as datum or set points for carving machinery? Can someone enlighten me? Thanks!

Also, the price of these carved rose cherry resin beads seems to have taken quite a downturn in the last few years!

jrj_09042019.jpg (105.6 KB)  


Modified by jrj at Thu, Sep 05, 2019, 19:51:56

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Are you sure they are carved and not molded?
Re: Question about miscellaneous holes drilled in Chinese carved beads -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/05/2019, 21:56:50



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Re: Are you sure they are carved and not molded?
Re: Are you sure they are carved and not molded? -- Rosanna Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/05/2019, 23:18:19

I should add that the photo is not of my beads, although I do have a few beads that are similar. The incised decoration on my beads is not uniform, which may bear on the reason for the small holes.

Back to your suggestion, I assume you're suggesting that round shapes were first cast and later cut or incised with decoration. Is this what you're thinking? How do you think the tiny recessed holes fit into the process? You can see one of these small holds in the bead that's directly left of the center of the image (and in a few of the other beads).

Thanks, Rosanna! I assume these beads (and my beads) are resin and not amber. Any thoughts about the material (without the benefit of scientific analysis)?



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Have you tried the reamer or Simichrome tests?
Re: Re: Are you sure they are carved and not molded? -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/06/2019, 10:04:33

If they are phenolic resin, you should be able to get a good result from either test. Please let me know if you need further instructions. You can substitute household ammonia for Simichrome.

The reason I asked about molding is that I recently bought a large bead that was advertised as carved Bakelite and if I had checked, I would have seen the mold lines in the photos. They were easy to see on the actual bead, which I returned since it was molded from polyester. However it really looked like a phenolic resin from the pix.

Also - it appeared that the bead was touched up after molding, so there were also "carved" surfaces to confuse things. So I'm assuming the basic pattern was molded in, then hand work touched up the piece to make it look ,well, hand-carved. Which in a way it was.



Modified by Rosanna at Fri, Sep 06, 2019, 10:07:28

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Re: Have you tried the reamer or Simichrome tests?
Re: Have you tried the reamer or Simichrome tests? -- Rosanna Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/06/2019, 13:58:03

Thanks! I'll try ammonia and report back.

The width of the decorative bands and the decoration itself is too irregular to have started out as molded detail, later enhanced by cutting.



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Rub a barely wet (with ammonia) q-tip on a smooth area. Will turn mustard yellow if phenolic.
Re: Re: Have you tried the reamer or Simichrome tests? -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/06/2019, 14:27:18



Modified by Rosanna at Fri, Sep 06, 2019, 23:33:00

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Test results
Re: Have you tried the reamer or Simichrome tests? -- Rosanna Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/06/2019, 20:31:55

I tried a barely damp (with water) Q-tip and the cotton turned very pale brown, which I assume is dirt. (I bought the necklace at an estate sale and it needs a cleaning.) Same result with ammonia. I'm a bit taken aback by these results because I had assumed the necklace was not amber. Rosanna, are these tests conclusive?



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Tests
Re: Test results -- jrj Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/06/2019, 20:59:41

I'll test it again tomorrow and photograph the Q-Tip and my beads. But before I do, I'd like to wash it to remove dust and dirt. Rosanna, if it's resin, can I wash it with a dilute solution of water and Ivory soap? Thanks!



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Avoid washing with anything harsh like 409.
Re: Tests -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/06/2019, 23:26:12

Mild soap like Ivory will remove both dirt and skin oils and will leave the surface intact for another ammonia test if you want to try again.
After washing a bead, do the ammonia test again and make sure you rub the q tip really hard this time. Some beads give very strong color change and others have a very faint color change. But it’s always mustard yellow.



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Your results indicate that it’s a plastic other than phenolic resin, or maybe real amber
Re: Test results -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/06/2019, 23:18:55

Yes, slight dirt on the surface will come up tan or brown. A deep mustard yellow color, which may be faint, is a result of a chemical reaction with the surface of phenolic resin. A phenolic bead from almost 100 years ago would give this color unless the beads had been heat treated, which is possible. But all the cherry amber jewelry beads I’ve tested gave a positive result in this test.
If you can do the bead reamer test you can confirm the ammonia test result. Ream the hole rapidly and take a sniff of the sawdust. Also observe the color of the sawdust by wiping it on a white cloth. If the bead is amber, the odor will be piney. If musty, medicinal, you have phenolic. If stinky plastic smell, it’s another plastic, probably polyester.

If you’d like to mail me one I’ll check it for you and send it back.



Modified by Rosanna at Fri, Sep 06, 2019, 23:35:02

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Photos of necklace and ammonia test results 1
Re: Your results indicate that it’s a plastic other than phenolic resin, or maybe real amber -- Rosanna Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/07/2019, 18:13:54

Photos of the necklace overall and a detail. Note the screw clasp mechanism which is glued into holes drilled in beads; these beads are slightly larger than the standard dimension and different in design. I don't want to take the necklace apart because the construction method used in creating this clasp doesn't lend itself to reassembly.

jrj_09062019_overall.jpg (201.2 KB)  jrj_09062019_dtl.jpg (175.0 KB)  


Modified by jrj at Sat, Sep 07, 2019, 18:36:17

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Photos of necklace and ammonia test results 2
Re: Photos of necklace and ammonia test results 1 -- jrj Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/07/2019, 18:19:29

Another detail of the beads and a photo showing the ammonia-dampened swabs used to test the red material. The swab used to test a bead in on the bottom and the swab used to test the red portion of the clasp is on the top. The color on the swabs looks a little redder in the photos than it actually is. I should mention that there's still "dirt" in the crevices of the beads and I think that's what's showing up on the Q-Tips.

I'm thinking the beads are not phenalic resin but another type of plastic.

jrj_09062019_dtl_2.jpg (176.3 KB)  jrj_09062019_ammtest_bd_bot_clasp_top.jpg (136.8 KB)  


Modified by jrj at Sat, Sep 07, 2019, 18:22:57

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Re: Test results
Re: Test results -- jrj Post Reply Edit Forum Where am I?
Posted by: cn Post Reply
09/18/2019, 15:10:58

you were wondering if your beads were amber.
have you tried floating them in a salt water solution. The specific gravity of real amber (and also copol) is less that salt water, so they will float. thats a sure fire test.



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Chinese carved beads
Re: Question about miscellaneous holes drilled in Chinese carved beads -- jrj Post Reply Edit Forum Where am I?
Posted by: stefany Post Reply
09/06/2019, 04:12:21

please give indication of size!
are they just holes on the surface or do they converge in the centre?
T-shaped holes have a purpose on prayer bead strands...



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Re: Chinese carved beads
Re: Chinese carved beads -- stefany Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/06/2019, 05:42:37

My beads are 13mm+/- and the randomly-placed holes do not extend to the center of the beads. The randomly-placed holes are in fact rather shallow.



Modified by jrj at Fri, Sep 06, 2019, 05:56:47

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Susan Dod's rose-carved cherry resin beads
Re: Re: Chinese carved beads -- jrj Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/06/2019, 05:58:44


I just looked at photos of Susan Dod's rose-carved cherry resin beads and some of hers have random holes. See the bead to the right of center at the very top in the below image.

Sdods_jjrj_09062019.jpg (152.5 KB)  


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These are 1930s phenolic plastic, carved in China—often sold as "cherry amber."
Re: Susan Dod's rose-carved cherry resin beads -- jrj Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/06/2019, 07:18:13



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There is more dark amber undertone to these beads
Re: Susan Dod's rose-carved cherry resin beads -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/06/2019, 15:40:28

So I can believe these are phenolic resin. Only a very thin outer layer turns cherry red with age & exposure unless heat treatment is used to drive the color change reaction.

For your first photo, I’m not sure. There doesn’t appear to be any amber undertone, but color photography that is underexposed like in that picture can mask a lot of features.



Modified by Rosanna at Fri, Sep 06, 2019, 23:31:34

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Sigh....
Re: There is more dark amber undertone to these beads -- Rosanna Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/07/2019, 01:53:51

From 1926 through the '30s and probably later, Chinese beadmakers made thousands or millions of translucent red phenolic plastic beads. The beads that have been marketed as "cherry amber" throughout my career (and long before, of course). The material was imported from Europe or the US, in rectangular blocks—and was transformed into beads via lapidary cutting, grinding, "carving," polishing, and drilling (just as would any industry that made phenolic plastic beads). The beads were most-frequently spherical or spheroidal (many being standard oblates). These fit in well with beads made for Mandarin Court necklaces. (I have them.)

Some beads were carved. Some were elaborately carved—such as the subject beads in this thread. (That I have seen before too.)

The material is generally uniformly red—just like the blocks from which is was derived.

While it is entirely possible that some tawny-yellow phenolic (and/or other plastic) beads have become superficially red over the years, scads of beads were made from red plastic. The tone of the material can vary. Many beads are uniform in color and frankly red in good available light. Others can be darker—and it helps to hold the beads against a light source to see their uniformly-dark-translucent red color. The material of the red Chinese beads is indistinguishable from red phenolic plastic beads made for the European market (often being faceted, and characterized as "Russian cut," and "Victorian" "cherry amber"). And the material is likewise indistinguishable from many (but not all) red phenolic plastic beads made for the Middle Eastern and African markets (except in instances where some beads MAY be yellow with a red exterior—due to age, heating, or dying).

So far, in the arena of Chinese phenolic beads, I do not recall seeing any "dark amber undertone" beads" with surfaces that "turn cherry red." But I have seen and documented, and I own, the beads I have described.

JDA.



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Would love to see and test one
Re: Sigh.... -- Beadman Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/07/2019, 06:05:55

Cherry red phenolic beads that look uniform in color can have a thin outer red skin. I fractured a nice old faceted one and discovered this. For the past 3-4 years the pieces have been sitting out on my desk and the fresh surfaces are slowly turning cherry red again. My hypothesis, based on reading the patent literature and other sources, is that many or all the cherry red beads started out amber yellow, and turned red under ambient conditions within a few weeks to a few years. It’s also possible that people liked the red color and it was deliberately induced by heating the beads. But the chemists worked hard to develop phenolic resins that had more stable colors. By the mid to late 20s color stability was mentioned in ads for various phenolic resin products.

I’ll try to post before and after pix of the fractured bead pieces. Unfortunately my before pictures are not the greatest and the pieces are tiny.

When the phenolic resin was made in solid red colors, it’s a different shade of red, at least to my eye. On my display I can see the amber yellow undertone but of course it’s impossible to ID for sure from a picture, and colors will vary on everyone’s computer.



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Fracture surfaces of faceted cherry amber bead
Re: Would love to see and test one -- Rosanna Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/07/2019, 14:42:39

First photo- taken in August 2016 - shows the thin cherry red "skin" on a clear amber yellow interior. Note that you can see the skin color only on the thin pieces. On thicker pieces, it looks like the interior is red since the original surface on the other side is red and the material is pretty transparent. A faceted bead from the same set is shown at the top of the picture.

Second pic was taken today - the clear yellow pieces are now tinged with the red color, turning them orange. It may take 10-20 years for them to become the cherry red color of the original surface. In the literature, there were reports of this color change happening in weeks. The chemical reaction that causes the color change at room temperature would be expected to vary with the exact formulation used, impurities in the mix, etc. etc. As stated before the phenolic resin chemists found ways to stop this from happening eventually, but with dozens of companies making similar products, I imagine the results were all over the place.

I accidentally bumped the tray a few months ago, otherwise the pieces would be in the exact same spot as they were 3 years ago.

I haven't fractured any other cherry amber jewelry beads so maybe I'll add that to my project list. I pretty much know what I'll find since when I ream cherry red beads enough to remove the thin skin from inside the hole, the resulting sawdust is amber yellow.

Jamey, do you have any fractured beads or pieces that can show that the cherry red color goes all the way through?

BrokenFactedPFBeadAug2016.jpg (50.1 KB)  BrokenFacetedPFBeadSep2019b.jpg (46.9 KB)  


Modified by Rosanna at Sat, Sep 07, 2019, 14:52:17

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I suppose the shallow concavities are just decorations (!).
Re: Question about miscellaneous holes drilled in Chinese carved beads -- jrj Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/06/2019, 05:56:31



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Beadman, I think you are right
Re: Question about miscellaneous holes drilled in Chinese carved beads -- jrj Post Reply Edit Forum Where am I?
Posted by: jrj Post Reply
09/06/2019, 06:14:07

On the better carved beads in my necklace, the shallow holes relate to the tops and bottoms of leaf-like shapes. These holes are not very distinct (I missed them previously) and they give the carving greater depth (emphasis) surrounding the leaves. On the less well carved beads, triangles are substituted for leaves and the holes are totally random. These are the very distinct holes I saw earlier.

I'll take pictures to post tomorrow. Thanks all!



Modified by jrj at Fri, Sep 06, 2019, 06:16:50

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For comparison - a recent "cherry amber" polyester bead
Re: Question about miscellaneous holes drilled in Chinese carved beads -- jrj Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/06/2019, 14:53:13

First photo - a quick glance made me think this was carved phenolic. Actually a 3.5" ball rather than a bead - has the 12 zodiac signs. After I realized it was new, I found many copies on eBay, some claiming to be real amber, for less than $30.

Second photo - the line where the two halves were joined is clearly visible. Close inspection at the right hand end of the line shows where the designs on the two halves don't quite match up.

Unless I inspect a plastic bead and do a few tests, it's very hard to tell what plastic was used.

I will say this about the Chinese "cherry amber" beads like yours though - it seems like there are "enough" of them on sale on eBay at any given time to make me suspect that some of them, at least, are recent production, probably from polyester resin. Could be that a mold was made from some hand-carved beads, then new ones were made from the mold(s). "Prices taking a downturn" makes me suspicious... OTOH all of them may be old phenolic.

RFDragonHead.jpg (85.9 KB)  RFMoldLineCloseup.jpg (105.9 KB)  


Modified by Rosanna at Fri, Sep 06, 2019, 14:56:54

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"... the line where the two halves were joined is clearly visible." Seriously?
Re: For comparison - a recent "cherry amber" polyester bead -- Rosanna Post Reply Edit Forum Where am I?
Posted by: Beadman Post Reply
09/07/2019, 01:57:13



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I’d show you in person but I returned the ball and got a refund
Re: "... the line where the two halves were joined is clearly visible." Seriously? -- Beadman Post Reply Edit Forum Where am I?
Posted by: Rosanna Post Reply
09/07/2019, 05:34:28



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