Moon is the significator of mind.It denotes mother, mind, brain,intellect,progeny. If in dark fortnight moon is afflicted then native suffers many problems. The mantras for moon are:
" ऊँ दधिशंखतुषाराभं क्षीरोदार्णवसम्भवम।
भाशिनं भवतया भाम्भार्मुकुट्भुशणम।। "
ॐ अमृतांगाय विद्महे कला रूपाय धीमहि तन्नो सोमः प्रचोदयात्।
" ऊँ स्रां स्रीं स्रौं स: चन्द्रमासे नम:
"ॐ ग्रां ग्रीं ग्रौं स: गुरवे नम:"।।
Pearl is the stone for Moon and can be worn if moon is debilitated in a horoscope or it is benefic in nature for the ascendant. Otherwise one can wear Sphatic Mala or White Agate as substones.