I have a huge purple faceted stone that turns multiple colors. During the day it is a dark to light purple turning a light pink towards the evening. At night it turns to a blue color inside the home. Going into the outside night it turns an even deeper blue. If I am depressed or I when I cry it turns white or clear color. I traded a friend for the stone. She removed it from a platinum setting. She said it might be an alexandrite, but she was unsure. I put the stone in another setting and whore it for around 6 years. Doing dish's and showers , never took it off until I accidentally hit my hand on a concrete wall and it fell out. I took a look at it and to my surprise  there was a few light scratch's on the very top surface, considering I have never had it cleaned, it looks in pretty good condition. What is it and can I just buff the small scratches out.or?