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counter for jewels in a watch
counter for transistors, diodes, etc. in an electronic product
「石」 has other readings with different meanings.
囲碁で黒石を使いました。
I used black stones in Go.
庭に敷き石を並べています。
I'm laying stepping stones in the garden.
宝石の価値を鑑定してもらう。
I'll have the gem appraised.