Hotrodlincoln Posted September 18 Share Posted September 18 Hello. I’m hoping someone can help me figure out what this is: it was given to me a few years ago by fellow rock hounder who said they thought it was the result of lightening striking sand. They found it in Arizona or California. I know absolutely nothing about these but it doesn’t look like the pictures I’m seeing on internet. Any thoughts? Quote Link to comment Share on other sites More sharing options...
DarkSilicate Posted September 18 Share Posted September 18 maybe plagioclase. And a further guess, anorthite. Quote Link to comment Share on other sites More sharing options...
chrisski Posted September 18 Share Posted September 18 I am by far not an expert, but the lighting strikes I know in sand make fulgerites. I think these things look like either tree roots or hard coral. What you have to me looks more like man made glass that has been in the ocean a little bit, but not yet smoothed out to sea glass. Quote Link to comment Share on other sites More sharing options...
Bedrock Bob Posted September 18 Share Posted September 18 Nope. That is not fulgerite. It is chalcedony. A common silica mineral 1 Quote Link to comment Share on other sites More sharing options...
d_day Posted September 18 Share Posted September 18 1 hour ago, Bedrock Bob said: Nope. That is not fulgerite. It is chalcedony. A common silica mineral Yep! Run of the mill chalcedony. Quote Link to comment Share on other sites More sharing options...
chrisski Posted September 18 Share Posted September 18 Did not mean to dirstract from the thread with a mis-ID of a fulgerite. I did not know about fulgertites to recently, so perhaps this is a better picture: looking at the OPs pics, who was told these were lightning strikes in sand, to me they look less likely to be created by lightning than the stone I posted earlier. I guess my question is, wouldn't these "Lightning Stones" be branched like the photo above, and not like a piece of man made glass broken off and exposed to the elements a bit? In case I'm confused, the pic above is a bit to transparent to be any Chalcedony that I've seen. The little I've found is White and opaque with a little bit of rust staining. 2 Quote Link to comment Share on other sites More sharing options...
Bedrock Bob Posted September 19 Share Posted September 19 2 hours ago, chrisski said: Did not mean to dirstract from the thread with a mis-ID of a fulgerite. I did not know about fulgertites to recently, so perhaps this is a better picture: looking at the OPs pics, who was told these were lightning strikes in sand, to me they look less likely to be created by lightning than the stone I posted earlier. I guess my question is, wouldn't these "Lightning Stones" be branched like the photo above, and not like a piece of man made glass broken off and exposed to the elements a bit? In case I'm confused, the pic above is a bit to transparent to be any Chalcedony that I've seen. The little I've found is White and opaque with a little bit of rust staining. Chalcedony comes in every shade you could imagine. It is most often translucent. Fulgerite are tubes. With branches. And kinda green when you look close. Very fragile. Like worm tubes only fused. Im no expert on either of them. But the OP's stone is definitely chalcedony. The clear kind. There are white desert roses and bright pink carnelian. Even irridescent blue varieties. But the stone in the first photo is regular old chalcedony from a volcanic flow. Chalcedony is not glass. It is agate. A fulgerite is fused silica or glass. It is more brittle and much softer. And is not microcrystalline like chalcedony. It is amorphous like obsidian or opal. Im not sure you can really see the glass in fulgerite without a lens. It is mostly grains of quartz sand fused together. But this specimen is definitely cryptocrystalline agate. And more specifically chalcedony. From an extensive volcanic origin. Quote Link to comment Share on other sites More sharing options...
clay Posted September 19 Share Posted September 19 Appears to have gas bubbles and holes. Looks like man made glass from a fire to me. 1 1 Quote Link to comment Share on other sites More sharing options...
Hotrodlincoln Posted September 19 Author Share Posted September 19 Thank you everyone for your input. So wonderful to find helpful people! so —yes I see what you are saying about the chalcedony. I have collected several chalcedony roses in New Mexico and I definitely see the similarities. Im not sure if my pictures show that it is clear with lots of “stuff” in it. I see the black specs of course but there’s also gold metallic pieces and lots of bubbles. So if I understand you correctly the bubbles don’t mean it’s man made, and the bubbles are present in chalcedony? And this stuff is volcanic? I’m posting some more pictures that might be a little bit better but hey I never would have guessed chalcedony. Good to know and my opinion it’s a pretty cool piece at that. by the way. I was pretty sure it wasn’t a fulgerite but was hoping it was something like melted sand from a meteorite splash or lightening striking a hunk of dirt😁 if you can zoom in on the second to the last picture you can see how clear it is, which made me think it’s man made Quote Link to comment Share on other sites More sharing options...
Bedrock Bob Posted September 19 Share Posted September 19 If there are bubbles it is glass. Quote Link to comment Share on other sites More sharing options...
DarkSilicate Posted September 19 Share Posted September 19 just for grins, do a hardness test on it Quote Link to comment Share on other sites More sharing options...
Morlock Posted September 19 Share Posted September 19 Looks like glass to me. Quote Link to comment Share on other sites More sharing options...
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