Thank you for submitting your item for appraisal. This appears to be a china head breastplate doll. These dolls have been popular since the 1830s and were in production in Thuringia in Germany until 1990. The dolls came out of fashion in the 1920s but the heads and spare parts were kept in production. There were lots of doll manufacturers in Thuringia, one of them was Hertwig & Co., possibly the manufacturer of the doll head in your possession. But this is hard to tell fromt the photo provided. Most breastplate dolls can not be clearly attributed to a certain manufacturer, as the thuringian manufacturers copied each other, the french manufacturers and vice versa. Hertwig & Co. had strong trade relations to the US market, therefore the likelihood is high. The prices paid online have dropped considerably, but if offered on an antiques fair with the right dress and the story to it you might be able to sell the doll for US $150-$250.