Help identifying rock/mineral

[Kathleen Anne]

I have a rock wall in my yard that was constructed in the early 1930's. It is made entirely of petrified wood, quartz, and others that I am trying to identify. The cement in the wall is starting to crumble and some of these rocks are falling out. I have sold some on ebay and some I keep for my collection. This particular one caught my eye because of the crystals surrounding something else. I'm not sure what it is. Thank you for your help.

 

[DDancer]

Getting some interesting stuff mining that wall Looks to me like you now have a geode with calicite filling the vug. Interesting combination. Those rock hounds were having some fun in the day.

 

[Eu_citzen]

I'm wondering if the host-rock is limestone?

 

[stdenis_jd]

agree with DD & EU both, looks like limestone matrix, calcite crystals

 

[DDancer]

Hrm, I'm not seeing limestone and the clear crystals are not calcite in my opinion. The rind looks like chalcedony/agate banding and the surface of the rind that I can see shows large coarse grains some semi-crystalline. I have seen geode vugs that have combinations of quartz and calcite and thats what this one appears to be. With this stone I cant say for sure if its a geode or just a vug taken or erroded out of a host rock.