Extremely high hardness, and a melting point that reaches billions of degrees.
She is very familiar with these physical properties; back then, they spent several years building the Crystal City.
At that time, the machinery used to construct the Crystal City was as large as a mountain, and it utilized the technology of alien invaders.
The fate of that machinery afterward is unclear; perhaps it was destroyed since it had the potential to threaten the Crystal City.
Having participated in the construction of the Crystal City, she knew well that relying on human technology alone, even with nuclear weapons, couldn't destroy the Crystal City.
If there were a super close-range explosion, it would most likely just break this red crystal into scattered pieces, but to completely annihilate it...
It's fair to say that relying solely on nuclear weapons is exceedingly difficult, almost impossible.
However, the weapon she brought from another dimension can compensate for this inadequacy.
