Looks a lot like an egg case for our Praying Mantis here. They are light brown, but very similar in 'nature'. The striations are a bit more pronounced, as in deeper grooves. The ones' I see are about 25-35 mm long and about 20 wide. Maybe? Do you have those odd little creatures in your neck of the woods? Suppose you could put it in a jar, and have it hatch in your kitchen, then let it go in the same place. Then again, it might imprint on you forever...that'd be fun.