Rare Australian Opal from the 1700s: Identification & Value

Question
I was wondering if you could tell me or research if there is a rare type of opal or gem stone that was found in Australia around the 1700's and not widely found or not found since then? I showed what I found to a local museum but they were not sure and gave me their best guess and made reference to it resembling very rare that was discovered somewhere in Autrialia in the early 1700's. What I have looks like it is opalized and has such a deep green color. I had person offer me $1000 for a size of it that just covered the tip of one of my fingers. I said no because I want to find out what I have before I set a price. I am filing a claim presently to the vein in which I found it as well.

Answer
Hi John , Australia was nt discovered until 1788,no outback adventure to opal areas till late 1800 Opal wasnt discovered until about 1880 that was Lightning ridge  . Ive not heard of anything like what your refering to. But I probably would have taken the $1000. Ive seen some of the oldest opal pieces held in Australia . There's nothing Ive ever seen that would match your description , the only possible match would be that it looked like jade and a chinese thought they could make  a tidy profit on it .Australia is large , all opal field are now well established ,if your find is outside the known opal areas , then theres every chance its not even opal. If you have na image or more details Ide be happy to help identify it . thats my best on your wording , hope that helps . Best regards Rod Keady  www.keadyopals.com