Trying ID This Rock

[Doughboy]

I purchased the stone with a bunch of others at a garage sale, I posted it on a different website where I was told it can't be identified with the pictures I provided so I figured maybe someone here can ID it, here is a link with all the info on the rock including picture

 

http://www.mineral-forum.com/message-board/viewtopic.php?t=1844

[Brainteaserfan]

I purchased the stone with a bunch of others at a garage sale, I posted it on a different website where I was told it can't be identified with the pictures I provided so I figured maybe someone here can ID it, here is a link with all the info on the rock including picture

 

http://www.mineral-forum.com/message-board/viewtopic.php?t=1844

The second one looks like slightly dirty quartz to me.

http://en.wikipedia.org/wiki/File:QuartzUSGOV.jpg

The first, I have no idea on.

[Realitycheck]

Looks like limestone, if it is reacting with vinegar, but it also does look somewhat crystalline. The picture is not real clear.

[Doughboy]

The second one looks like slightly dirty quartz to me.

http://en.wikipedia.org/wiki/File:QuartzUSGOV.jpg

The first, I have no idea on.

 

 

They are all the same stone

[Brainteaserfan]

They are all the same stone

Wow, the lighting must be very different for the two photos. This, "not from the piece in the previous photo but from a different one" is what lead me to believe they were different, sorry.

[tectobunny]

Looks to me like a gypsiferous limestone

[Iggy]

it's about 4-5 hardness I would say closer to 4 with a white streak and I would say it has a silky luster to it... If it helps, the stone fizzes a little in vinegar, more like little bubbles come from the stone and I can hear a slight fizzing sound, it doesn't fiz up like vinegar on baking soda in fact it don't foam at all and when removed from the vinegar after being in it for 15 minutes it formed a white film on the surface

 

I also would have guessed limestone... dolomitic limestone (it reacts weakly to acid). Can't really tell from the pic though.

 

... edit... "dolostone" might turn up a better search than "dolomitic limestone" ...edit...

Edited August 6, 2011 by Iggy