When to be careful wearing a gem for the Moon

Gems for the Moon should not usually be worn when there is phlegm, edema, congestion, or when overweight (high Kapha). Psychological factors are strong emotions, sentimentality, greed, attachment, or excess involvement with family or society.

Astrological factors are the Moon is a malefic lord (lord of houses like the third, six and eight, as for Taurus, Aquarius or Sagittarius ascendants). When such a malefic lord, the Moon can cause problems even when full.