What is the prayer written on that piece of jewelry?
Om mani padme hum.
Aum= a sound, it is the imperishable sound of the universe at creation. (People chant Om or Aum to resonate with the universe.)
Padme = lotus
Hum=a sound, it is the sound of triumph when all beings become enlightened.
The jewel within the lotus represents the mystery of life. It is the budding complexity within which dwells the jewel of truth.
So, saying that it means, "A jewel in a lotus," is accurate, but it doesn't really explain what it is about.
Many people simply repeat the chant with the expectation of sudden enlightenment, or that with each repetition they are one more step closer to Nirvana. But the general idea is that it is a prayer for others as well as for oneself. It is a prayer for all sentient beings to become enlightened. As consciousness is raised throughout the world, the benefit to all of us is realized.
*This is my take on what I have read or been told. No doubt, there are other interpretations.