Refers to the marine organism or its calcareous skeleton, often used in contexts like coral reefs, jewelry, or aquarium keeping.
The coral is growing slowly in this sea area.
There are many beautiful corals in the sea around Okinawa.
This necklace is made of real coral.
In the old days, people used to harvest coral on this island.
She is wearing a necklace made of coral.
珊瑚 is a calcium-carbonate skeleton formed by marine polyps, whereas 琥珀 is fossilized tree resin (amber); both are prized as organic gem materials but come from completely different sources.
Usually written in katakana; usually written in kana.
Kanji form is used in formal or scientific contexts, but katakana is more common.
Hiragana spelling is also seen, though katakana is typical.
The word is of Chinese origin (珊瑚, shānhú in Mandarin), borrowed into Japanese. The katakana spelling reflects its common use as a biological term.
coral wedding anniversary; 35th wedding anniversary