It has been known for some time that chimpanzees fashion tools from wood, including spears with the ends ground to a point on stones. That some would also fashion tools from stones should not be a big surprise.
That chimps
use stone tools is not a surprise. It's been well known for decades. They do not, however,
fashion. Chimpanzee stone use involves finding a convenient stone and hitting things with it - they do not modify the stone for use. It's possible to discover archaeological evidence of stone tool use because of characteristic wear on the tools.
The human stone age, on the other hand, we usually consider to begin when humans began modifying stones for use, which no other primate is yet known to do. Simply using stones isn't limited to chimps either - some species of capuchins and macaques both do so, as it says in the article you linked to.
™ Version 4.2
