A pearl: a round, lustrous gem produced by mollusks, often used in jewelry (often interchangeable with the katakana word 'パール').
祖母から真珠のネックレスを譲り受けた。
I inherited a pearl necklace from my grandmother.
真珠はフォーマルな場面でよく使われる宝石だ。
Pearls are often used for formal occasions.
真珠の価値は大きさ、光沢、形で決まることが多い。
The value of a pearl is often determined by its size, luster, and shape.