Moonstone is associated with the Goddess, actually all the Goddesses, from the Great Mother Goddess but especially the moon goddess. It was once believed that moonstone was made from moonlight:

In the Orient, people believed Moonstones were actual rays of moonlight that had solidified, and that the shimmering light held within the stone was a good spirit that lived there. Hindus thought shimmering Moonstones to be earthbound bits of moonbeams, and the stone is still considered sacred in India today. – CrystalWind

Moonstone is said to support the crown and pineal chakras, although the peach one is said to influence the heart chakra according to this site specifically for the peach moonstone:

Peach Moonstone’s gentle, loving energy supports the heart as it stimulates the mind.

This same site also notes that it’s “the keeper of the feminine mysteries” and that “the frequency of Moonstone encourages us to pay attention to the cycles of our lives.” I suppose this is why I have always believed that it helps with feminine problems and our monthly cycle.

My own experience with a wonderful piece of peachy orange moonstone was relief from my monthly cramps. It was a real boon, and was such a soothing stone for that time of the month. And I know it wasn’t just me…I have given this stone to other women who were complaining of cramps, and they were amazed that it helped! And one of these women wasn’t even sure if she believed it would help, but she was desperate for relief and no one had any pain relievers in our small office. An hour or so later, she came up and hugged me, amazed that the stone had indeed relieved the pain and pressure. I made a believer out of her, and she went out and got herself her own piece!

The last person I lent it to was my sister, and I must have forgotten to cleanse it, for the next time I went to use it, it broke apart into 5 little pieces, almost like it splintered. I now keep it in a little container, but this is only one of several rock pieces I have over-used in the past that wound up giving its life up for me. It always saddens me to have them break into pieces, but I honor them and stop using them. They say you can bury them and return them to the earth, but since I rent, I don’t want to do that. Some say that you can give the pieces to others, spreading the love around if you will, but I think if they’ve broken it’s because it’s used up, and best to let it rest somewhere safe, and recharge. I don’t like to reuse them.

Anyway…I can totally vouch for the effectiveness of peach moonstone for feminine problems, menstrual problems and cramps. Just make sure you cleanse it well!