What are the conditions for the Aqiqah for a male newborn, and is the weight of his head hair given in gold or silver?

"The 'Aqiqah is a confirmed Sunnah. It is preferable for it to be two sheep for a male and one for a female. It should be slaughtered on the seventh day after the child's birth. What suffices for the sacrificial animal (Uḍḥiyah) from the livestock also suffices for the 'Aqiqah. It is also recommended to shave the child's head on the seventh day and to give in charity the weight of the hair in silver."