Single word for "able to blend in"

I am writing about an analogy that is made in a text that I am reading between a substance that blends in to the point of being incapable of being identified as a distinct object (like a certain type of flour into another, when they are mixed) and an object that remains a distinct object, even when blended with other like objects (like, say, a marble).

Is there a single word for the type of substance that blends (the flour)? It's not exactly dissoluble (flour doesn't dissolve)...

The sentence is:

Whether the item is _____ is one of the factors that determines whether it corrupts the mass into which it is blended.

Solution 1:

Miscible: from chemistry

Definition of miscible : capable of being mixed specifically : capable of mixing in any ratio without separation of two phases

Might sound a little odd in a social context, but it fulfills your, apparently multiple-liquid, situation.