What are the two rule of noun?

Proper nouns are the unique names of people, places, or things. Proper nouns are always capitalized. Examples:

• Napoleon
• Australia
• Statue of Liberty

Proper adjectives are adjectives that are derived from proper nouns. Proper adjectives are always capitalized. Examples:

• There is a block of Victorian houses on this street. (houses from the era of Queen Victoria of England)
• The chair is Italian leather. (leather produced in Italy, known for its high quality)
• The scene before us looked like a Martian landscape. (as if a scene on the surface of Mars)