Hitachi, the company who unveiled these storage devices claim that these can last up to a few hundred million years if not longer. The glass slivers are made of quartz, an extremely stable compound that can withstand temperatures beyond 1,832 degrees Fahrenheit and is chemical and water resistant.
The data is stored by creating dots that can be read with a microscope. Those dots can be interpreted by eye (if you can read binary code) or with a computer and with a square inch of this material you can store 40 megabytes onto each layer, each sheet has about 4 layers and can easily add more.
Though we will have to wait to use this because Hitachi is not releasing these for practical use yet. Like most things, government organizations will get their hands on this first.
Via Mother Nature Network