Answer:
The materials are opaque or crystalline from a client to the orientation and type of union between their atoms, forming two types of structures.
These two structures can be crystalline or amorphous.
In the case of being crystalline, these unions do not allow light to pass through the medium of the object or body of said compound, making it totally refract and giving the appearance of OPAQUE.
On the other hand, in those compounds that we call amorphous, the atoms are located in a different way that makes light pass through them, without absorbing or identifying any light beam, so they look transparent.
Explanation:
Example: A glass cup has an amorphous structure, while a porcelain or porcelain plate has a crystalline structure.
