Obsidian is an igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. It is an amorphous material known as a  mineraloid .. The result is a volcanic glass with a smooth uniform texture that breaks with a conchoidal fracture (see photo on right). Obsidian is usually an extrusive rock-one that solidifies above Earth's surface. However, it can form in a variety of cooling environments: Black is the most common color of obsidian.
â¢ PEP TALK (noun). The noun PEP TALK has 1 sense: 1. a speech of exhortation attempting to instill enthusiasm and determination in a team or staff. Familiarity information: PEP TALK used as a noun is very rare.
An old-school American slang from the 50's which means litterally quiet, used in conjunction with gossip. Off the record, on the QT, and very hush-hush. -- Danny Devito's character in the file L.A. Confidential.