Once in a great while, I am able to get ahold of this unique material found in Pakistan. this Herkimer Diamond-like Quartz Crystal is included with Petroleum. It looks yellow under normal light, and under long wave ultraviolet it fluoresces a brilliant blue color. A normal clear Quartz would look black or invisible in the bottom two pictures, using the ultraviolet light. It was found in central Pakistan in a region that is war strifed, and dangerous. (no Pakistani mineral dealers ever want to go there!). This is a complete crystal, which is rare for this occurrence, as most crystals are just broken pieces. It weighs 14.53 carats/ 2.91 grams.

Quartz with petroleum inclusions