Opal is inadvisable for people with a weak Venus; such people need to remember that the gem may not bring positive outcomes. Opal is also advised against people with birth signs like Cancer or Scorpio because this stone has the ability to intensify mood swings. Opal Side Effects & Disadvantages can be significant if worn without professional advice from an astrologer, leading to different sorts of negative impacts such as anxiety, restlessness, and sensitivity. Besides, it can even cause worsening of other existing health problems associated with the kidneys, urinary system, and the reproductive system. Before wearing opal, it is wise to seek advice from an astrologer familiar with the adverse effects of this gemstone on a particular birth chart and its Zodiac sign.