The phrase "irreplaceable asset" is grammatically correct and can be used in written English.
It is typically used to describe something or someone that is extremely valuable or important and cannot be replaced. Example: "The company's CEO was an irreplaceable asset, with decades of experience and a wealth of knowledge that was crucial to the company's success."
"We thought it was an attractive opportunity because we felt that it was an irreplaceable asset".
"It would be a tragedy if Mir were 'de-orbited.' It's an irreplaceable asset".
"This is truly an irreplaceable asset for the National Park Service," Mr. Front said.
"I believe I'm an irreplaceable asset with my family," he said, "but Apple is an amazing company that would go on without any individual, including myself".
Despite Wall Street speculation about Mr. Jobs's importance to the company, he said he did not believe he was an irreplaceable asset at the firm that he helped found.
The coterie of senior executives involved – Peter Fincham, then the controller of BBC1; his boss, Jana Bennett, the director of television; BBC creative director and senior corporate talent fixer Alan Yentob – believed that Ross was an irreplaceable asset, a sort of "Heineken" man, someone who could reach the parts of the audience others couldn't.
Some of our transportation systems -- from our highways to the New York City subway system -- represent irreplaceable assets that could never be built from scratch in this economy.
In sum, Palmyra is an irreplaceable biological asset.
At risk is an irreplaceable natural asset that happens to be dying.
New York is an irreplaceable national asset; our governor and our mayor must see to it that it is treated as such.
The fund invests in art by postwar, deceased or nonproducing artists, which Castlestone's owner and chief executive, Angus Murray, said he considered "an irreplaceable real asset".
