| Also slang for low-grade Crystal Meth. A bag of shards weighs a quarter gram and varies in price from $20 to $50, depending on purity, luck and location. Upon closer observation one can notice pieces of different sizes, ranging from three millimeters to fine dust. Usually, the dust is abrasion from the larger pieces mixed with filler.
By the time one purchases it, white shards take a few weeks to turn yellow, at which point it is supposed they go bad. However, most people consume them far before they reach this state.
An eighth of a gram keeps the average person up for two days, making the splitting of a bag for a party common practice. Key bumps are used for short bursts of energy.
Also, if you didn't know, this is (health-wise) one of the worst drugs you can do. Last time I indulged I came down with a throat infection a few days later, while my girlfriend got a sore throat -- basically, your immune system is rendered useless. | 
