can I just use my necklace as a pendulum

Yes — a pendant on a chain works fine, and the physics of a swing is the same. What matters is that the weight hangs straight, free, and doesn't rub.

A few things that make a necklace less steady than a proper pendulum:

• Heaviness — a small pendant drifts and its own tilt confuses the direction. A bit of weight (20–40 g) and a small size swings cleanly.
• Chain friction — a fine chain is fine; anything that catches, or a long necklace looped and twisted, adds drag.
• Symmetry — if the pendant is lopsided or the clasp sits off-centre, it hangs tilted all session.

So: hold the chain between thumb and forefinger, rest your elbow on the table, sit still for a minute first, and give it 20–30 cm of swing over a marked spot on the floor. Ask a question you genuinely don't know the answer to first — that's your baseline.

The honest part: the swing is a magnifying glass on your own expectations and small muscle tremors, not a message arriving from outside. That's exactly why the known-answer and unknown-answer tests matter — if the movement doesn't stay flat on the neutral ones, it's reading your expectations, not the question. Use it for focus and for a "which of these two do I already lean toward" check; don't let it decide things a doctor, a lawyer, or the actual document should decide.

If you want, I can draw a single card to sit alongside the question you're asking the pendulum.