Hi Aviendra,
Crystals can hold energy and so it is possible that the Amethyst is holding onto something. Of course the crystal can be saved
I don't know how much you know but in cases like this I would pull out all the tricks and smudge the whole house, cleanse the Amethyst under cold running water, and then take some protective measures.
Hold the crystal under cold running water, a mountain stream or the shallow waves of the sea, the main thing is cold, water, and movement. Imagine all the darkness and negativity and past energies being washed away by the water and becoming one with the Earth where thay can do no harm. If possible run the water over both hands too and then shake dry watching all the tiny droplets of water leave taking all the unwanted with them

Dry your crystal on a natural cloth, cotton or linen or silk. Then leave it somewhere prominent, somewhere that you can pass the crystal and infuse it with your ambience and nartural energy.
Other good crystals for this are Black Tourmaline and Black Obsidian, they will protect and send back any directed energies. Smudging I have posted about in Occult and Magick