I have enclosed some pix of a jar that I just got. It was sold as 18th.Century. From the photos, I thought it should be Kangxi Period. Alternatively, a little later. When I got the jar today my first reaction was that it is 19th century.
The glaze is rather dull in color. It's a greenish-brownish-grayish color and is darker than all my 18th.C. pieces. It does not have the brilliance and crispness of color that my other pieces have. There is a great deal of variation in the color of the paste and glaze in 18th century pieces but this piece does not seem to fall within the boundaries.
The paste where it is exposed is rougher than I would have expected. The foot rim has a triangular profile that I associate with the 19th century. In addition, the gilding on the mountains is shaded which seems strange. Is there any way this could be 18th century? I would appreciate any input you might have.
I have seen quite a few 18th century Chinese Export pieces and to me this seems to be quite ok but above average as for the quality. I have seen several pieces like this I have not seen any reason to doubt and I do not feel there are any reason to doubt this either. I feel these jars should date to about the mid 18th century, even if they usually are called "Kangxi" by the trade.
As for a simple test, I feel you could just lift it to find out its age, since it should be quite heavy. "Heavier than it looks", as I use to put it, is a good rule for pieces of this early to mid 18th century.
I do not think this could be 19th century really, since the style is way off of what was appreciated at the time.
If there is something wrong with it at all I feel it in that case should be modern, but a modern copyist would most probably have missed out on this with the weight, and just molded it to get the shape right.