The consistency of something that breaks under pressure(noun)
WordNet. Princeton University. 2010.
Use "breakableness" in a sentence
"Reply Obj. 1: As rarity and density remain under the sacramental species, as stated above (A. 2, ad 3), so likewise porousness remains, and in consequence breakableness."
""I fancy that the breakableness is in the nature of the heart itself, and not of the iconoclast," said Cecil."
"Of their dead selves to higher things; but the beauty, and excellence, and glory of love, the exceeding profitableness of enduring grace, and the sweet aroma of faithfulness, will be the more clearly manifest to the sons of men by reason of the weakness and breakableness of the human vessel."