Any Rock Hounds out there

[Ernie Nyvall]

A family member who saw some of my work with turquoise, pulled these out from an old truck and gave them to me. Each of the rocks in the jars contains one or more opals. Some are full of fire and and look really nice. I took a bad picture of one. Anyone out there know how to extract them from the rocks? If I can get them out, would they work imbedded in wood or do they have to be wetted periodically to keep them from drying out?
Thanks for looking.

Ernie

[Joseph O'Leary]

From my days as a lapidary I can give you some insight, although I have only cut opals into cabochons, I have never tried to inlay them. It would not be necessary to continually wet them. Opals are usually kept in water so that it is easier to see the fiery bands of color. The notion that they need to be continually whetted comes from the fact that the "fire" comes from thin layer of hydrated quartz. There is old advice that says you should wipe the face of an opal with mineral oil every few years. I doubt that many people do this and their opals still stay brilliant. Opals are rather soft stones and are easy to grind, they are however brittle so I would not try to chip or break the groundmass that surrounds the fiery color you are after, unless you are after a lot of real small chips. Lapidaries often use wet carborundum grinding wheels. if you have a grinder you can get a 6" 220 grit wheel and a spray bottle and grind away what you don't like. Whenever I cut opal I would rough out on a 220 wheel and do all my final shaping on a fairly worn out 220 sanding disc, wet of coarse. It's that soft and easy to grind. I am certain that you would have no problems inlaying in a clear epoxy or other type of resin. Many commercial stones are what are called doublets or triplets, the fiery opal is so thin that it is sandwiched in a resin that is then cut and polished to produce a stone of substantial proportions. Hope this helps.

[Bill Turpin]

The single stone looks like it is from Mexico or SW US. The old story was that the fire was from embedded water. I do not know if this is true. However, if you get an opal too hot while cutting the fire will go away. Just like as if the water boiled away. The same old story was that the surface finish of polished stone SEALED in the water. Since the water leaves on a molecular basis, it is doubtful that a finish with 325 grit polish would stop a very, very small molecule. A scratched opal will lose it's fire. I think this is "applied science?" to fit the evidence, not the fact.

Carefully wet grind off excess or crush with hammer. Then embed in thick CA or slow cure, water-clear epoxy. The glue should keep water or whatever from exiting. Opal is quite soft and can be scratched with sand or steel. Carefully design the stone surface to not be exposed to harder materials.
A layer of solid black underneath clear opal will increase the fire.

How to become a rockhound: Put fifty glass marbles in a heavy, canvas sack. Every time you find a pretty rock, put it in the sack and put one of the marbles where you found the rock. After you have lost all your marbles... you are an official rockhound.

Bill in WNC mountains

[Bill Lewis]

Bill, does WNC = Western North Carolina? My father grew up there, and I can remember he used to have a bag of garnets that he found when he was a kid. I don't know what happened to the garnets, and he has long since passed away. That area sure seems to be a "rich" rockhound hunting ground. I bet you lost your marbles pretty quickly.

[Bill Turpin]

I live about 25 miles SE of Asheville. I spent my boyhood as a Florida tourist in WNC. The car usually leaned to my side due to the rocks. Unfortunately most of the rocks here are not cutting grade. The true cutting materials are mostly now part of very over-priced tourist traps.

However there are many locations where BB to pea sized garnets can be picked up loose from the soil. They have their many crystal faces, but internal fractures make 98% uncuttable.

Bill in WNC mountains