admin answers:

Take it to your local jewelers to have it appraised. Request that they do the evaluation in front of you instead of taking it to the back of the store, where they might do some switching. Then take it several other places and compare the appraisals.

admin answers:

Opal is a mineraloid gel which is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, and basalt. This silica based gemstone comes in many colors white, black, pink, red and blue.

Moonstone is typically a potassium aluminium silicate. The most common moonstone is of the mineral adularia. The plagioclase feldspar oligoclase also produces moonstone specimens. Its name is derived from a visual effect, or sheen, caused by light reflecting internally in the moonstone from layer inclusion of different feldspars. Typically they are silver gray to peach in color with a white or blue sheen.

Opal tend to have a more varied colored surface as to the one note sheen of moonstone.

admin answers:

I believe Moonlight Opal is a regular white opal mixed with Mica,which can add myriad reflective shafts of light in addition to the overall Opal's soft moonlike glow.

It is also a natural occurring stone, but there are moonstone opal glass that you may be thinking of...

admin answers:

Opal is one of the mineraloids that can form or replace fossils. The resulting fossils, though not of any extra scientific interest, appeal to collectors.

There are many kinds of opal, and they all are mined much the same way as any mineral, and cast into jewelry, or made into carvings.

You can grind the rock off with the right abrasive tool on a grinder. You may be able to chip most of it off.

Check this site out to find out the kind you have. Http://en.wikipedia.org/wiki/Opal#Precious_opal

If the field has much rock with opal in it you might want to invest in a polishing kit which will help you shape it into jewelry or carvings.