How can you tell a stone is a sapphire..

[Nikos]

Guys how is it possible to tell if a find is corrindium?

 

[Lefty]

It looks a bit like chrysoprase but I'm not an expert there. I wouldn't say it was corundum - where did you find it Nikos? Did it get caught in your sluice?

 

[Ben78]

My first thought was Prase too.

 

[Nikos]

Found it in a creek bed..I initially thought phrase as well but once I had cleaned it..I began to doubt..some areas on the edges go from green..to clear..to blue..gold in some areas..it's translucent..phrase is cloudy..waxy..

 

[Ben78]

Peridot? Sapphire fractures chonchoidally, the same as glass and quartz

 

[Heatho]

Looks like Chrysoprase to me also, with some of its host rock still attached. 100% certain it's not Corundum.

 

[Wally69]

A specific gravity test may give you a reasonable idea. Being such a big size the accuracy should be good.

Nice find

 

[Nikos]

Cool..how do u do a gravity test?

 

[Heatho]

This one works well Nikos. http://johnbetts-fineminerals.com/jhbnyc/articles/specific_gravity.htm

 

[Nikos]

That's awesome guys..thanks Heath for the link!

 

[Heatho]

No worries mate, Col posted it up a while back, easiest way I've tried.