The Vajra family is associated with the color blue, the element of water, and it is located in the east of the mandala. In an encumbered state, this family is associated with the emotional poison of anger, both hot rage and cold passive aggression, while its enlightened manifestation is Mirror-Like Wisdom, a vast and precise cognizance that reflects everything with great clarity, yet remains unaffected by what reflects in it.
“Vajra” is a Sanskrit term usually translated as “diamond” or “thunderbolt,” and refers to a divine ritual scepter used in Indian and Tibetan tantric traditions. The vajra represents indestructibility, power, transformation, and the sacred masculine (paired with the bell, representing feminine wisdom). In its most common five-pronged form, it represents the transmutation of the five poisons into the five wisdom energies. Enlightened wakefulness is indestructible and unconditioned, and cannot be tarnished or harmed; the vajra symbolizes that wakefulness.
You can find the entire set here.