1. Indistinctly crystalline; - applied to rocks and minerals, whose state of aggregation is so fine that no distinct particles are visible, even under the microscope

Encyclopedia: Cryptocrystalline

• hard-shelled
• hard-skinned puffball
• hard-to-please
• hard-wearing
• hard-won
• hardback
• hardbacked
• hardbake
• hardball
• hardboard
• hardbound
• hardcore
• hardcover
• harden
• Hardenbergia
• Hardenbergia comnptoniana
• hardened
• hardener
• hardening
• hardening of the arteries
• hardfisted
• hardhead
• hardheaded
• hardheads
• hardhearted