Yes, the plural noun 'diamonds' is a common noun; a general word for any gemstone form of carbon; a general word for a geometric shape.
A proper noun is the name of a specific person, place, or thing; for example "Diamonds Are Forever", the title of a book and a movie.
No, jack of diamonds is a common noun, a word for a playing card; any jack of diamonds in any deck of cards.
The collective nouns for diamonds are a cluster or diamonds or an arrangement of diamonds.
The most common use of diamonds is for industrial tools, because industrial diamonds are the most common diamonds.
The possessive form for the plural noun diamonds is diamonds'.Example: I had the diamonds' settings checked by a jeweler.
The pronoun that would replace the subject noun 'thief' is 'he' or 'she'. Examples:He stole the expensive diamonds. OR, She stole the expensive diamonds.
Common
Common noun
common
Pea is a common noun, and peas is the plural...still a common noun.
A common noun.
Most definitely a common noun.
When describing diamonds, glass is probably not as common as ice.