Metropolitan Museum of Art
Metropolitan Museum of Art: Costume Institute: Search the Collection
This vast collection of historical garments and jewelry contains an inventory of over 34,000 items. Includes images, dates and important facts about each piece.
Other
Antique Enamels and Jewelry: Paintings in Glass
This site has an explanation of various enameling techniques along with photograph examples of each technique. Links to other jewelry sites as well as a list of books related to the topic.