Delectatione in varietates Yunnanes

[Figleaf]

Clockwise from upper left:

• Obv right: top upturned left, bottom rounded. Rev right: top and centre bungled. Coppery, magnetic.
• Obv right: top straight with complete triangle. Rev right: bottom bungled. Slightly coppery, magnetic.
• Obv right: top straight with broken triangle. Brassy, magnetic.
• Obv right: top upturned right. Slightly coppery, non-magnetic.

Number 4 is 26 mm. Others are 25 mm.
Number 1 is 4.9 grams, number 4 is 3.6 grams, the others are 4.0 grams

I suspect that numbers 2 and 3 are genuine and number 4 is an imitation. Don't know what to think of number 1.

Peter

[bgriff99]

This is not such a delectable pile.   

#1 is Guizhou/ Kweichow, not Yunnan.
#2 looks like a circulation forgery, but the weight is high.    Can you post an obverse image only, at maximum file size?
#3 is Dongchuan but not clear if old or new mint.
#4 is probably Yunnan-fu, about 1765.   There is a mystery there, because the engraving work of Guangxi-fu mint appears
   also with Yunnan-fu markings at this time, in large quantity.    This is one.   Obviously over a 60 year reign Yunnan-fu would have had to replace engravers
   of mother cash several times.  The larger mints shared or transferred engravers at various times. 

Zeno now has expanded its Qian Long and Jia Qing Yunnan sections to separately list all the branch mints, and their varieties.
The scarcer mints have a limited number of posts (i.e. mostly mine), so it's more catalog-like. 

[Figleaf]

Sorry, I need to ask additional information to digest this.

• I wasn't aware of a mint in Kweichow and can't find any such coins with Google. If the second and third stroke from the top are not connected it starts to look like Tientsin (See G and U here), or do you mean there was a mint somewhere in Kweichow that minted Yunnan coins?
• I'll send a high-def scan by mail.
• That would be Dongchuan mint in Yunnan province?
• Is it not unusual that this one is lighter, larger and not magnetic?

Peter

[bgriff99]

1.  Kweichow actually had two mints.   But both used 'boo kiyan'.   They are very common, having been cast the entire reign.
     Your Qing mintmark guide skips it.

2.  Yes Dongchuan/ Tungchuan mint in Yunnan Province.

4.   Weights varied, but trended at mid-reign to be about 3.8g.   If it is broader, its weight was probably not intended to be that
      low.   Magnetism came from depleted mines, or locally high iron content.   None would be above 2% iron.  I'm surprised the one
      with holes is that heavy.

      Composition of all is brass.   Officially they were supposed to have a couple percent tin, but almost never did.   They are supposed to have
      lead, and sometimes do.   Occasionally Dongchuan substituted antimony and even arsenic for lead and some of the zinc.   Brass cash
      develop a surface layer of pure copper, even exposed only to air.   The higher the zinc level, the faster it happens.    "Brassy" versus "coppery"
      is not a feature except in regard to patina.