This mantra means 'Om to the light of Universal Friendship.' The mantra honours the first of the 12 gifts of the sun, and is the first mantra chanted during the yoga sequence known as the Sun Salutation. The Lovers represents the importance of love and relationships in our lives, relationships that prove to lead to a new understanding of life, of sources of help, and emotional support.
The natural crystal choice for this card, to me, is rose quartz. Use a rose quartz mala for counting off 108 repetitions of this mantra.
Chariot: 'Om gum ganapatayei namaha'
This mantra is dear to me as it is the first one I learned and used to effect. It means 'Om to Ganesha,' the breaker of obstacles. Also called Ganapathi, he is the obstacle-breaking power personified. The Chariot card also signifies a person successfully controlling some situation through the force of his personality. Success, a victory. This mantra is often chanted to help us achieve the outcome we want.
Black obsidian is suggested when using this mantra, but I prefer carnelian, as I associate Ganesh and carnelian with the root chakra.
Justice: 'Maakaral shivaya nama'
Though not a literal translation, this mantra in essence means: 'Salutations to Shiva, remover of karma'. The word 'maakaral' is derived from 'maha karal', meaning 'great stain', which refers here to great misdeeds or actions that produce very negative karma. The mantra is about removing negative karma, things being made right. The Justice card is closely associated with the concept of karma. Its appearance in a draw indicates first that events have come to you from decisions or actions in the past, and second that you see the truth of this outcome. At the same time it shows that your actions in the future can be changed by the lessons you have learned in the present situation. Honesty, fairness, right actions, just decisions. Both carnelian and jade are suggested as stones to accompany the Justice card. I myself have not yet decided what crystal to use.
All images from Kat Black's Touchstone Tarot.