Ruby is the one which can induce signification of Sun in your life, so before touching Ruby make sure Sun is positive or negative in your horoscope or not.
Ruby which is also called Manik, will make or break your relation with Father, fatherly figure or authority, Government depending whether Sun is functional benefic or malefic in your chart.
Never wear Ruby with Neelam as the lord of these two gem stones Sun & Saturn are inimical to each other.
As Rahu is the one which eclipses Sun so its advisable not to wear Ruby with Rahu stone Gomed / Hessonite.
Only wear Ruby if Sun is having lordship of Kendra or Kona (quadrant or trine) house and posited weak or afflicted in horoscope.
Sun is the key significator of good health as it’s the natural ruler of 5th house Leo, which is 12th away from 6th house of disease. But too much activation of Sun may give you sun stroke, high fever, baldness etc.
If Sun and Saturn are conjunction in horoscope, then first make sure who is benefic among these two planets, figuring out that, you may wear the stone of that particular benefic planet during the mahadasha of that planet.
Suppose for Libra ascendant, Saturn & Sun conjunction in 1st house Libra, where one is 11th house of benefit lord Sun who is debilitated, another Saturn is yoga karak exalted. Wearing Ruby will surly effect the qualities or action of your Yoga Karak Saturn in your life. Hence better not to wear anything to disturb the situation.
If you wear Ruby in above situation, your education may suffer, your relation with children will be suffered, your overall fortune will not favour you much as you are giving strength to your yoga karak Saturn’s enemy Sun.
Aries, cancer, Leo, Sagittarius, Scorpio ascendant natives can wear Ruby as a gem stone to improve their life for positivity.
Ruby should always wear in gold ring.Only Sunday morning around 10 AM Ruby should be worn after reciting Sun’s Beej Mantra facing East direction.
Anamika or ring finger is the one allotted to wear Ruby gem stone.
Though Sun is the planet of Power, authority, confidence, having high post in society or Government, good health, high vitality, strong personality, wearing Ruby can also give snobbish behaviour and unnecessary ego clash with people as the by product of Sun characteristics.