The most likely expectation is that these are polymerizations of blood protein. That would explain the continuity, the fibrous structure, and the filaments. The "crystals" seem like mineral crystals---but from what is hard to fathom. An example needs to be assayed to determine the chemical identity.
Reminds me of a science-fiction novel by Christopher Hodder-Williams, in which something has gone astray, turning living tissue into polymer.
The most likely expectation is that these are polymerizations of blood protein. That would explain the continuity, the fibrous structure, and the filaments. The "crystals" seem like mineral crystals---but from what is hard to fathom. An example needs to be assayed to determine the chemical identity.
Reminds me of a science-fiction novel by Christopher Hodder-Williams, in which something has gone astray, turning living tissue into polymer.