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.
Where you actually meet it
补钙 (bǔgài) to take calcium supplements
The element itself
Almost all the calcium in commerce was put there by living things: limestone is compacted shell and skeleton, and chalk is a sediment of microscopic armour plates shed by plankton, which is what the white cliffs of the English Channel actually are. Burn limestone and you get quicklime, one of the oldest chemical transformations humans learned, and the basis of every mortar and cement since. Marble is the same material recrystallised by heat and pressure — the fossils cooked out of it, the calcium unchanged.
Where it sits among the 118
First isolated in 1808.
In living things
Calcium plays two utterly different parts. As a mineral it is hydroxyapatite, the crystal that makes bone rigid and enamel the hardest tissue in the body, with the skeleton doubling as a bank the blood can draw on. As a signal it works because cells go to great trouble to keep the calcium in their cytoplasm around ten thousand times lower than the concentration just outside — so opening a channel for a few milliseconds produces a jump that nothing else in the cell could imitate. Muscle contracts when calcium binds troponin and drags a blocking strand off the filaments; a synapse fires when calcium triggers vesicles to fuse. In the sea, the same ion becomes shell, coral and chalk.
In Chinese history and language
Jade is not an element, but 玉 yù has a formula: nephrite is a calcium-magnesium silicate of the tremolite-actinolite family, a felted mass of interlocking fibres that makes it tough rather than hard. That toughness is the whole point — it can be sawn and abraded into a ritual disc thin enough to pass light, and it will not chip the way glass or quartz does. The Neolithic workshops that made those discs used stone from sources close to hand, in the lower Yangtze and the northeast. Only later did the material of 和田 Hétián, in the Kunlun foothills of the far west, become the jade that connoisseurship actually meant: pebbles gathered from the rivers draining the range, and carried the length of the country eastward along a road that was in use long before anyone traded silk on it.
Where it comes from in China
For calcium, look at the karst of Guangxi and Guizhou — a vast spread of limestone laid down on a shallow tropical platform, then lifted up and left to dissolve in warm rain. The result is the tower and cone landscape around Guilin and the Li river, which is essentially calcium carbonate being carried away in solution, one drop at a time. It is the largest continuous karst terrain in the world, and it is also why so much of the southwest has thin soil and rivers that disappear underground.
The full entry
For stroke order, example sentences, audio and the complete set of meanings, see the dictionary entry.
钙Calcium in the dictionary →Others built the same way
Every one of these carries 钅, and every one is a metal.