Hello,
Jewel means : Edelstein , Juwel, while
jewelry has the meaning of : Schmuck = rings, earings... ect...
Schmuckstück is a compound: der Schmuck + das Stück > das Schmuckstück = one single piece
2. -chen: This is used with diminutives:
der Hund > das Hündchen
die Katze > das Kätzchen
All nouns ending in -chen are neuter, that's the reason why we say: das Mädchen , although a girl is a female person - we are talking about the grammatical gender of the noun.
3. - schaft: All nouns ending in -schaft are female:
die Wissenschaft
die Kundschaft
die Gesellschaft
die Wirtschaft - ect.
This ending has no special meaning.