ولا تصح المرابحة ولا التولية حتى يكون العوض مما له مثل
Translation: Murabahah and tawliyah require the initial countervalue to be fungible or replaceable in kind.
A fungible consideration is one that can be specified and replaced by an equivalent of the same type and quantity, such as a known sum or measured fungible goods. This makes the first price reliably carry over.
When the original consideration was a unique nonfungible object, its estimated monetary value is not automatically the original contractual price; the situation requires separate treatment.