Charm with unusual inscription

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Obverse: four unknown characters
Reverse: four unknown characters, probably the same as on the obverse, but in simplified form.

Diameter: 41 mm
Weight: 22 g

Message from Alex Chengyu Fang (20-Dec-2001): It's a very nice piece. The script is described as Sanskrit by Chinese numismatic works. A similar piece is also featured in Francois Thierry's book on Chinese and Vietnamese charms. I don't think the meaning is yet known but suspect it relates to fortune, longevity, and honour (chang ming fu gui).
Message from Sergei Shevtsov (21-Dec-2001): This charm is listed in "Chinese Ancient Charms Compendium" ("Zhongguo Gudai Yasheng Qianpu"), Lu Zhenhai, Liaoning University, Shenyang, 1991, pages 1-823.; at page 725.
Lu Zhenhai wrote: "This is a silver charm, insciption is in Sanskrit, the meaning is unknown.".

Vladimir Belyaev (21-Dec-2001): Shown charm is definetly copper or brass, not silver.
Characters are similar to Sanskrit, but in my opinion are not the same at 100%.
Look at the page

Eric Yin (21-Dec-2001): The script on the amulet looks sanskrit-like, but I wonder if it is really is?
12:00 position possibly looks like "am/om" if you squint really hard
3:00 position kind of looks like "cha/jha" with an accent mark
6:00 position the left hand element looks like "ha", but the right hand element? Perhaps two accent dots?
Is it possible that these are some of the sanskrit based scripts like Xi County script, Tiancheng script, or Junshan Cliff Carving script that were used for transliterating Chinese transliterated sanskrit?
Anybody know what these "secret" scripts actually look like?

Gabriel, website (21-Dec-2001): Yes, they are somewhat similar, but I bet they are not Sanskrit ones. However, one character in the symbol on the right is somewhat similar to "hriing" mantra ("ng" stands for anunaasika), but it may be a mere coincidence. Besides, the dot on top of ardhacandra (half-moon) looks rather like a drop. Granted, Devanaagarii is not the only alphabet to write in Sanskrit, but I have not seen so far any other characters like these in Kharosthi or Brahmalipi alphabets (the other two ancient alphabets to write in Sanskrit). I think that they are chinese signs or something.
Richard Wells (23-Dec-2001): I think your charm may be either Siamese, or Burmese; the characters I think are stylized Chinese ideographs.

Any additional information highly appreciated.
Chinese Coinage Web Site