Silkstone is a durable material that simulates the weight and feel of porcelain. All of the dolls in the Barbie Fashion Model Collection are manufactured from Silkstone. The Barbie Fashion Model Collection is a line of dolls introduced in 2000 by Mattel, Inc. The collection features dolls aimed at the adult collector, primarily sold via Barbie collector websites and online retailers. To date, all of the female dolls have featured the 1993 re-sculpt of the original Barbie face from 1959, with updated facial screening and a variety of skin tones, hair colours, and fashion ensembles. The collection has also featured the Ken character, and as of 2011, the Francie character. In 2010, a line of dolls based on characters from the AMC television drama Mad Men were produced.