Limestone crystal help!!!?

Question

(i recently went to the singapore science centre and bought this limestone which contained crystal,so i broke it apart and found some shiny crystal like thing inside so i would like to ask if anybody knows what it really is...
pls help me

and also if it is worth money?
ps: i bought it for S$5

pls help me

its is really quite shiny and it can really scratch glass

Answer 1

Limestone is made of calcite (CaCO3) so it is possible that your crystal is a calcite or aragonite crystal that has grown within a cavity in the limestone. However, calcite will NOT scratch glass in a normal scratch test. Calcite has a hardness of 3 on Moh's scale and glass has a hardness of about 5.5 to 6. Calcite can be clear, white, brown, or less commonly other colors.
Here is Moh's scale of hardness:
http://www.rockhounds.com/rockshop/hardness1.html

Here is a picture and more description of calcite crystals:
http://www.mindat.org/min-859.html

Quartz crystals are common and will scratch glass. Quartz has a hardness of 6-7 on Moh's scale. Quartz is commonly clear, but can come in any color.
Here is a picture and more description of quartz crystals:
http://www.mindat.org/min-3337.html

The rock you are describing might be a geode, in which case it is common to find a hollow center that can contain different types of mineral crystals. Here is a description of geodes:
http://www.desertusa.com/magjan98/jan_pap/du_rock_geode.html

The best way you can identify your mineral is to go to the Mineralogical Society of America website where they have an online mineral identification key that you can use to diagnose your mineral online:
http://www.minsocam.org/msa/collectors_corner/id/mineral_id_keyi1.htm

Quartz and calcite are the two most common crystals that you might find, but many other minerals are possible. I also suggest you go to mindat.org and just browse through the thousands of minerals there, and you will see some other possibilities. You can also search the site by rock properties, so if you identify a certain property of your crystal you can use this to narrow the search.
http://www.mindat.org/

Answer 2

I'd need more info to answer this. What does the crystal look like? What is it's lustre (is it shiny?)? Does it scratch glass or can you scatch it with a coin?

It's possible it's just a calcite crystal, in which case it's not worth much. I'd be suprised if it's a valuable crystal.

Answer 3

the crystals in the limestone can very well be quartzite a hard see through crystal.

Answer 4

i was at school and a boy brought a rock and put it on the floor. Then a little third grader took it and brook it in half.He asked if it was gold in there and me and my friend annakay martin said yes.we tried to get it but he ran only four feet away then he droped both pices and ran. we brook it into smaller pices and found cristals in it.

Answer 5

i dont know what you have but go to this web site may it will help you.www chemistry.about.com