Natal Jupiter is the sign where your JUPITER was placed during birth time, and from there other houses are calculated clock-wise.
If you were born with Jupiter in Gemini, then your natal house is Gemini (Mithuna Rasi) and during transit, MARS forming conjunction (in Gemini), sextile (aspect of 60° which are Leo and Aries in this case), square (aspect of 90° which are Virgo and Pisces here), trine (aspect of 120° which are Libra and Aquarius here), opposition (aspect of 180° which is Sagittarius here) are discussed in this article.
Conjunction is transiting through same sign as in birth chart, sextile is transiting 3rd or 11th house, trine is transiting 5th or 9th house, opposition is transiting 7th house from natal sign.
Transit MARS conjunct Natal Jupiter : You will develop impulse to expand feelings and ambition.
Self confidence increases as there will be adundant energy, vigour.
Over confidence and ability to undertake any amount of physical work can lead to unnecessary risks, danger of accidents and losses.
You will be lured into ways of making easy money, speculation. Success in such areas is possible only due to self confidence and planning, but not by luck.
This is also best time for new enterprise, foreign travel, inheritance, legal affairs, joint ventures.
Do NOT forcefully impose your religious views on others.
Transit MARS Sextile Natal Jupiter : Practical insight into business and professional affairs.
You will be ready to communicate and negotiate advantageous deals.
Being clear in objectives can achieve desired results.
Time is good to deal with legal matters and those in authority.
Your religious, educational, political ideas and beliefs will be conveyed successfully.
Sports persons can also have good time.
Transit MARS Square Natal Jupiter : Your optimism is unjustified. Take it for granted attitude will backfire.
Impulsive behaviour, carelessness can lead to unnecessary expenditures and losses.
Extravagance and losses are also possible due to thefts and misappropriations.
There will be tendency to go beyond limitations and resources, only to face a collapse.
Misdirected ego can lead to attempts of domination over others, unethical ways in business and financial affairs.
There will be problems in joint finances, inheritances, law suits and matters related to dead people.
Be careful in long distance travel.
Transit MARS Trine Natal Jupiter : You are generous, kind, noble to people around.
Energy levels will be twice the normal.
You will spend more than usual, but still do not incur losses.
Avoid risky ventures and invest money or energy in known areas.
This transit is favorable for putting religous beliefs into action.
Good time for sportsmen, people with foreign contacts, alimony, joint ventures, legal affairs, inheritances etc.
Transit MARS Opposition Natal Jupiter : Overconfidence can lead to foolish acts, wastage of resources.
Feelings and emotions can override analytical thinking in matters of investments and finance.
Exhibiting dogmatic attitude, fanaticism, over expression of sentiments, domineering attitude towards others can lead to resentment.
Empty promises, legal affairs, foreign affairs should be avoided.