* Sanskrit didn't have pencils: Sanskrit is an ancient language, predating the invention of pencils. They used other writing tools like reed pens (लेखनी, lekhani) and brushes (पट्टिका, pattika) for writing on palm leaves or other surfaces.
* Modern terms: You could use modern Sanskrit words derived from English, like "पेन्सिल" (pensil) or "लेड पेन्सिल" (led pensil). However, these aren't strictly traditional Sanskrit.
* Descriptive terms: You could use a descriptive phrase to convey the meaning, such as "लेखन साधनम्" (lekhan sadhanam) which translates to "writing tool."
Therefore, depending on the context, you could use one of these options, or even create a new Sanskrit word based on the properties of a pencil.