What you describe is definitely NOT a pencil sharpener. It is an opium bowl, or a fragment thereof. The opening that is about 1 cm in diameter is where the bowl would screw on to the actual pipe, which is generally a long shaft through which the smoke is inhaled. I worked on a Gold Rush era site in San Francisco's Chinatown several years ago and we found lots of these opium bowls, in many different designs. I seem to recall that the cone shape was fairly prevalent, as was the bronze patina and the Chinese characters. I don't recall what kind of literature we found on these artifacts, but museums often have good books and catalogs from exhibits -- try the DeYoung in San Francisco or the Sackler in D.C. Also any "gray literature" from CRM reports of Chinese sites in the west. Good luck! Julie Abell [log in to unmask]