A yad is a piece of silverwork before it is a ritual object, most often cast or hand chased by a silversmith into a slender rod ending in a small closed fist with an extended index finger, though wood and other metals are used for plainer examples.
Construction and regional styles
Sephardi and Ashkenazi communities developed distinct decorative traditions for the same basic form, filigree work and chain attachments in some regions, plainer turned wood in others, and a yad is commonly commissioned as a gift for a bar or bat mitzvah, engraved with the recipient's name and the date. A small chain often links the yad to the scroll's mantle or crown so it is never set down loose during the reading.
Why it exists, and what happens to a broken one
Its entire purpose is contact avoidance, a reader's finger tracing the text would deposit oil and moisture onto parchment meant to last centuries, so the pointer takes that wear instead. A yad carries no text of its own, so a broken one does not require burial the way a worn Torah scroll does, it is simply repaired or replaced, and old ones are often kept as family keepsakes rather than retired formally. Some yad pointers are engraved with a verse or the Divine Name for ornament, and where that is the case, disposal follows the more careful custom given to any object bearing the Name rather than being treated as ordinary metal.