Okay, I think this is the proper way to introduce the rockhound thing. The picture is of chert, the uglier cousin of agate and jasper. Chert is used for knapping, as in making arrowheads and such. This hunk of chert has a huge depression that has small stalactite structures that have precipitated out and one is, to me, a bit suggestive of something else.
![chirtin 022.JPG chirtin 022.JPG](https://ww2aircraft.net/forum/data/attachments/776/776438-7a284203ff780bff284d73994de3475f.jpg)
![chirtin 019.JPG chirtin 019.JPG](https://ww2aircraft.net/forum/data/attachments/776/776439-76585a96d437f07cf270a9a1a45ac1c4.jpg)
![chirtin 021.JPG chirtin 021.JPG](https://ww2aircraft.net/forum/data/attachments/776/776440-1844e49002d93f210d381fbc00f5d762.jpg)
![chirtin 022.JPG chirtin 022.JPG](https://ww2aircraft.net/forum/data/attachments/776/776438-7a284203ff780bff284d73994de3475f.jpg)
![chirtin 019.JPG chirtin 019.JPG](https://ww2aircraft.net/forum/data/attachments/776/776439-76585a96d437f07cf270a9a1a45ac1c4.jpg)
![chirtin 021.JPG chirtin 021.JPG](https://ww2aircraft.net/forum/data/attachments/776/776440-1844e49002d93f210d381fbc00f5d762.jpg)