Ok on my next one I try getting the struck end to purple as you described before and test it out. thanks. 

There's a wonderful book you might try to find, "20th Century Toolsmith and Steelworker." I suggest scrolling on iforgeiron to Book Reviews and then clicking on Survivors' Library. You'll find a url which offers many smithing books by title and downloadable in PDF. You may load "American Blacksmithing, Toolsmiths' and Steelworkers' Manual 1911" and go to Chapter VII, page 122, and read on about tools for granite, marble, limestone, and sandstone. Two books are combined in this volume, the second one being the toolsmiths' manual.

This book has good line drawings of the tools used in various trades. The author is dealing with high carbon steel of various carbon contents, not alloy steel. On the market, there is a good tool steel called "drill rod" which comes in 3 foot lengths. It is W1 (plain carbon, high carbon) has about 1% carbon content. In the early days, it would probably have been in an octagonal cross section, but now is sold in round section. I get mine from Travers Tool, but you can also contact MSC or McMaster Carr.