The metal radical 钅 files 铅 among bronzes and irons; the right side lends sound. Lead was the soft gray metal of ancient cosmetics and coffin liners — and when graphite sticks arrived from Europe, Chinese named them 铅笔 'lead pens' by the same mistaken analogy English did.
铅笔 is every Chinese child's first writing tool — characters are learned in pencil, erased, and rewritten until the strokes sit right. The 2B pencil holds special national status: it's the only instrument allowed for filling in 高考 answer sheets.
The soft metal 钅 that flows like marsh water 㕣 — LEAD, of pencil fame.
Pencils never contained lead — graphite was misidentified in the 1500s — but both English 'pencil lead' and Chinese 铅笔 preserved the error forever.