I sent a message to a friend of mine at the GIA early in the week, but to no avail. The hammered look is one that is immediately recognizable and everyone knows what it means (good coating), but the "why" escapes.
Boo, you can find Strack's Website here:
http://www.strack-gih.de/
The book is notoriously difficult to get. I discussed putting a way to order her book right here on Pearl-Guide with Elisabeth Strack. But we have not done it yet. She is pretty dissatisfied with the way her publisher has distributed the book. Her market is here - clearly. But it is nearly impossible to get her book here...