This image is an extreme close-up of a portion of a steel engraved die, the original image area you are viewing is but 15mm X 20.1mm, that's way less than one inch square, and the digital image is approximately 34 inches wide at 240dpi. (Needless to say what you are viewing has been reduced for use on the internet.)
Visible at this clarity (although we will soon be able to provide even clearer images at this degree of enlargement) are several factors that go into what is this die.
First, it is both etched and touched-up with engraving, the tell-tale granular texture of the bottom of the deep areas is because etching corrodes the metal, thus rendering it much less light reflective than engraving.
Second, notice that some areas (the tops of the arches at top, right) reflect light and look smooth like ice. The engraving tool polishes the metal so light bounces off of it like a jewel.
Other areas of interest are the rust not noticable with the bare eye and the very interesting texture all around the edge (left and bottom) made by the file that beveled the edges of this 1/2" thick steel die. Also, there are many surface scratches that would not print with an engraving press but look kind of spooky here.
While creating this image it was discovered that, at this extreme magnification, minute vibrations blur the image. So, now we will work on stabilizing everything for absolutely maximum focus (and we will be able to get closer, too.)