1) Looks like Agate but it's like a rock
2) Yellow Crystal
3) Brown Rock ( Looks like a Crystal and it's shiny)
4) White Crystal
Top 3 all look like calcite to me.
The last one could be quartz with some inclusions.
Can you tell anything about the hardness of the stones? Do they scratch glass? Or does glass scratch on the mineral?
Only the last one scratches glass
Then that is not a calcite; rather a white quartz or agate.
Ok then thanks for your help!
The top banded ones look like travertine as indicated by the banding habit and color. The best way to test is with an acid test - apply a small amount of acid and see if it effervesces.
It reacts to Hydrochloric acid (HCL) , it dissolves
It is a calcite.
Great that you did the acid test! Did it bubble vigorously?
It doesn't react so vigorously but it makes potholes wherever I put the acid
The videos are on Mediafire they are not infected with viruses , there you can see how they react.
That really cool; thanks for sharing!
I recorded how they react with HCL but it seems that only the sound was uploaded , sorry .
I downloaded the videos; no problem there!