Emerald releases cold green rays. The colour of the Earth element is green. Therefore green is a positive force with power of interaction. It is suitable for nervous, heart troubles, blood pressure, ulcer, cancer, headache, neuralgia, influenza, syphlis. It governs central nervous system, abdomen, speech, tongue, eyes, lungs, nose. Worn by a women it helps her to attract true love and if worn by a man he will attract a loving wife. If it is given by one lover to another and if the love between them grows cold then the colour of the stone will change from bright to dull. It protects its wearer from black magic and will confer allround prosperity and good health. It is ruled by Mercury.