Unbreakable (adjective)

1. Not capable of being broken or damaged.
2. Impossible to break, damage or destroy.

Origin:

Mid 17th century: from un- (meaning 'not') + breakable.

Examples:

1. The glass was unbreakable, its strength and durability ensured by the latest technology.
2. The chain was unbreakable, its links made of a special metal that could not be cut or broken.
3. The lock was unbreakable, its mechanism so complicated that it defied any attempt at picking.
4. The safe was unbreakable, its walls made of a material that could resist fire, water, and theft.
5. The diamond was unbreakable, its hardness and clarity unmatched by any other precious stone.