How the character is built
The 钅 radical marks this as a metal, and that is not a coincidence of this one character — it holds right across the table. Read the radical first and the element's state at room temperature is already settled. It is 金 (jīn) squeezed into the space beside another component — radicals change shape by position, which is why 金 is hard to spot until you know to look for 钅.
This character is used for the element and little else — you are unlikely to meet it outside a chemistry classroom.
The element itself
Indium is soft enough to be marked with a fingernail and will leave a streak on paper like a pencil, and when bent it emits a faint crackling sound as its crystals slip past each other. It was found by its indigo spectral line, which gave it its name. There is no such thing as an indium mine — it substitutes for zinc in sphalerite at trace levels and is recovered from zinc refining residues, which caps how much of it can ever exist regardless of demand.
Where it sits among the 118
First isolated in 1863.
Where it comes from in China
Indium has no ore. It substitutes for zinc inside sphalerite at trace levels, so it is recovered only where zinc concentrates are already being smelted — in China, the tin-zinc systems of Dachang in Guangxi and the zinc districts of Yunnan. This is the general rule for the scattered metals: their supply is decided not by exploration but by what somebody else is smelting anyway.
The full entry
For stroke order, example sentences, audio and the complete set of meanings, see the dictionary entry.
铟Indium in the dictionary →Others built the same way
Every one of these carries 钅, and every one is a metal.