Testing anxiety relieving effects of crystals

Came across this neat study from another board:

Placebo effects in alternative medical treatments for anxiety: false hope or healing potential?

The setup:

The randomized controlled study ... included 138 nonclinical adults: 70 crystal believers and 68 nonbelievers. Within each belief group, participants received rose quartz or a visually similar glass stone, then followed a 14-day routine. Anxiety was measured before and afterward ...

The findings:

anxiety scores declined among believers, whether they received rose quartz or the glass stone; nonbelievers showed no reliable improvement. Crystal users did not improve more than placebo users ... Prior beliefs strongly predicted perceived efficacy and symptom change; pre-study expectations predicted 87.7% of post-study belief ratings.

(Above from the credo summary)

So not surprisingly, crystals don't inherently reduce anxiety.