Lew,
Thanks for the clearer picture.
The blade's diamond cross-section should extend all the way to the base of the blade. In this example, it seems that the thickness is not enough to form the base properly, which is approximately 1/2" or 1.5cm (it does vary).
This is how the base should look like for this type of blade.
(Example, courtesy of BluErf's gallery.

)
http://www.kampungnet.com.sg/modules...view_photo.php
From the first picture, there seems to be no sign of a temper.
Example of a 'visible' tempered blade, (courtesy of BluErf's). A two-toned finish.
http://www.kampungnet.com.sg/modules...view_photo.php
Kind Regards,
Shahrial