Obscure Horror Movie Question.....Help Needed!!!!!?

I once saw a horror movie a few years ago, the story took place at this girls-only Catholic college / prep-school. There was some construction going on at the school and a small group of girls made a underground discovery. There was some hidden chamber with this spooky mystical cauldron. Some in the group were sort of "gothy" and into magicks and the occult. I think they then started to try and use the cauldron to work various spells.

Some things about the film I remember were rather distinctive. The girls "activated" the cauldron by reciting spells as they all walked around it in a circle. One girl, the presumed leader of the group, had a memorable scene where she did a bit of a strip-tease in front of a window for a young construction worker. And I think the setting was somewhere in the Western United States, somewhere with a desert climate.

Anyway, I was trying tell someone about the film but I could not for the life of me think of the name. Does anyone have any clue what the title might be? Points to the one who can give me the correct answer first.