The phrase "a mere piece" is correct and usable in written English.
It can be used to emphasize the insignificance or triviality of something, often in a dismissive context.
Example: "He considered the award to be a mere piece of paper, not a true reflection of his hard work."
Alternatives: "just a fragment" or "only a small part".
Instead of spitting out a mere piece of paper, it produces an actual object.
Perhaps it was nave to expect a mere piece of clothing to remain a symbol of America.
So when one monkey was handed a grape in exchange for her token, the second was reluctant to hand hers over for a mere piece of cucumber.
"If you don't support the price," Andrei V. Polyakov, a spokesman for Alrosa, said, "a diamond becomes a mere piece of carbon".
Amal, sassy and spirited, knows a mere piece of fabric isn't a barrier to ambition — like the real-life Aussie who designed the first "burkini" for Muslim women to wear at the beach.
And if they are dismissive of marriage as a mere piece of paper, or an unnecessary legal bond, then why are they so keen to turn to the law for compensation when the free union ends?
" If some of the props in Endgame could belong in a museum, all concerned with making the drama are adamant that it is not a mere museum piece.
Although saturated with the cultural peculiarities of its time and place, this film is too alive to be a mere period piece.
Free agency would allow Paul to choose his future team, but this strategy would functionally allow him to create one of his own; it would make Paul a player rather than a mere playing piece.
During the evolution of the dugout canoe the sides were raised by means of planks, and this led to gradual reduction in size of the dugout portion until it became a mere keel piece, with the rest of the hull built of plank.
Without spoiling the specifics, the scene becomes a mere genre piece, a seeming advertising symbol for a generic kind of outlaw freedom on the open road that both breaks the texture and substance of the film and, more important, highlights the fundamental misconception on which the film depends.
