These are double terminated, Herkimer diamond-like, quartz crystals from Pakistan that contain petroleum (oil) inclusions. When viewed under visible light the petroleum inclusions look like little wispy yellow/brown blobs inside the crystals. When seen under UV the petroleum fluoresces bright blue/white, making the inclusions look like beautiful sparkling stars in a night sky. The largest crystal is 26mm in length.
Petroleum quartz crystals seen under visible light (top image) and long wave UV (lower image).
Mouse over scrolling images to see UV wavelength information.