Simple categories matching crumbly:

• item,
• cheese,
• food,
• rock,
• material,

Members with property crumbly:

• sweetened_cereal,
• cracker,
• croissant,
• slate,
• biscuit,
• magnesium_alloy,
• muffin,
• toast,
• stilton,
• popcorn,
• dry_cereal,
• brass,
• pretzel,
• pumpernickel,
• bronze,
• crisp,
• flaky_cracker,
• danish,
• cereal,
• bread,
• cake,
• dry_toast,
• mica,
• glass-fiber_paper,
• rice,
• fruit_cake,
• ricotta,
• parmesan,
• potato,