I noticed recently that the facets on the crown surrounding the table on a diamond-cut Imperial Pink Zircon, which I purchased a year ago online, appear to have dull patches in the center. The facet edges are not discolored or abraded, rather the phenomena seems relegated to the center of the tiny peripheral facets. I do not see pitting or gouges, just what at first looked like an oily film that cleaning did not remove. Odder still, on some of the dull patches, I see a slight bluish cast, or a faint discoloration.
What seems to be the more likely explanation: A) The Zircon, which was sold to me as unheated from Tanzania, was in fact treated --- perhaps a bulk diffused Topaz or Quartz? --- and it is a surface color treatment that I see wearing off; B) the stone, which was set last year into a six-prong ring mount, has sustained abrasion or chemical damage (wear and tear); or C) the jeweler's torch, in setting it into the prongs, caused a slight heating effect causing the Imperial Pink stone to take on the faint blue hue I detect in some of those patches? (Notably, the dull patches don't run beneath the prongs and there is no dulling of the table --- the rubbed-out marks in the surface polish appear only on those facets that reside between the Tiffany-style prongs.)
In closing, what I have described may or may not have been present for quite some time; however, only recently did I take note.
Explanations would be much appreciated.