Re: Hard a quartz - Is this petrified bone?
I am a senior geology student in kansas; this is definitely a chert nodule wrapped in limestone, as mike said. here in kansas these are everywhere, also the "bone" texture and unique shape you see is caused by weathering of the limestone. chert is a microcrystalline form of quartz, hence the observed hardness. Anyways, I hope this helps.
From Rene - March 05, 2010 at 08:42:40