The phrase "a mirror upon" is correct and usable in written English.
It can be used metaphorically to suggest reflection or examination of something, often in a philosophical or introspective context.
Example: "The novel serves as a mirror upon society, revealing its flaws and virtues."
Alternatives: "a reflection of" or "a lens through which".
He should know: Not only has he tracked the ways we fabricate our identities in his newest book, "Self Comes to Mind: Constructing the Conscious Brain" (Pantheon), but he also has a ready example of his own, a mirror upon which he has reflected for decades.
It forced a mirror upon itself, often in reflection of its adolescence, to find a greater version each time.
In place of a lens, telescopes rely upon a mirror that collects light and focuses it onto a detector.
This complaint can be repeated every time we chance upon a mirror.
We as artists are charged and almost obligated to maintain culture and be a mirror for it, to reflect upon it and show our current times.
My mom was my rock, my best friend, a mirror into which I gazed upon my past, the person I am today, and with any luck, who I just might become.
I feel sorry for these poor kids, who are the victims and the prey of screeched media advertising and who, upon looking into a mirror, see not themselves but a glossy composite of a dozen products.
If you are trying on something in a mirror at a Next store, reflect upon this: shop assistants in the giant clothing chain on average cost the taxpayer an estimated £2,087 a year in the form of tax credits, to make up for the fact that Next pays its workers so little.
This beam forms a standing-wave upon reflection from a mirror.
Once I was before a mirror, I found it a surprisingly difficult decision to act upon.
It tipped 45 degrees upon the pressing of a button hidden behind a mirror.
