From the pattern:

Named for the irrepressible town that is the haven of liberalism, The Berkeley Hat is so called for its liberating style and good knit fun. A deceptively simple stitch shows off Alchemy’s silk/merino bulky Lux fiber in its full handpaint glory to a wearable unisex hat.

This design was written exclusively for Alchemy yarns, and Alchemy is not responsible for the success of making it in any other fiber.