Karen Hetzer Artworks

What the heck is 'metal clay' I asked myself?  Can't remember how I landed on this website Craftcast.com but land there I did.  Its a website that offers recorded and live craft lessons and while there were no current live classes listed there was quite an extensive list of downloadable recorded lessons that could be purchased, the majority having to do with working with 'metal clay'........I'd never heard of it?  Not surprising though since I don't create jewelry or even wear it much but.....I'm intrigued.