Hitachi has created a sliver of quartz glass 2cm square and 2mm thick with the storage density of a CD, 40MB/in2 which they claim will remain viable for millions of years.  Even radiation, water, most chemicals and heat above 1000C will not damage the data stored on this chip and in theory dropping it shouldn't hurt it too much either.  Long term storage is a real problem, in some cases paper documents have a better chance of surviving long term in a readable state than do optical or magnetic media.  That doesn't even bring readers into the loop, there are many obsolete formats which cannot be read by current readers and finding an old working Zip drive is not an easy task.  Hitachi told The Register that they foresee no problems increasing storage density which is good considering the size of crystal you would need for large sized storage.  As long as someone can read the binary etched into the glass they would recognize that there was data stored there, on the other hand what is the likelihood they would be running a compatible file system.  At least the data will still be there which is more than you can say for the vast majority of storage media used today.

"Company researchers displayed the storage unit, consisting of a sliver of glass 2cm square and 2mm thick, which can hold 40MB of data per square inch, about the same as a standard CD. The data is written in binary format by lasering dots on the glass in four layers, but the researchers say adding more layers to increase storage density isn't a problem."

Here is some more Tech News from around the web:

Tech Talk