Lapidaryforum.net
Let's Rock => Rock Talk => Topic started by: RutherfordbHaye5 on January 24, 2019, 12:53:19 PM
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Let me start by saying im a noob when it comes to cabbing. I got a rough stone with small silicate deposits recently and I cut a small slab off it to get a better look at the insides. I suddenly had to leave and left the cutting oil on the stone for around 24 hours. When I came back to it the stone looked significantly darker, even after giving it a wash. What does this mean? Is the stone more porous than it looks and absorbed the oil? Is mineral oil not a good thing to leave on a stone? I'll try to post some pictures but the resolution is too high on the ones I have so I need to retake them tonight.
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Virtually all stones are porous to a degree.Stones with a high feldspar content can be quite porous as well as some opals of course and even quartz gems.Porosity is what allows agate to be dyed. Some stones should not be cut in oil and if they are they should be cleaned immedistely. Taking a small piece of the rough and putting it in water for a few days helps tell if there will be a problem. If the stone is more translucent or gemmy after being hydrated it is quite porous and will revert to its less translucent state after it loses the pore water. People sometimes say polishing locks the water in , it does not.
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Thanks for your reply! Turns out the rock isnt workable anyways, too many pits. This is still a good thing to know for future specimens!