Geologyhound

Keep in mind that if something is molten, it would adhere to anything it touches unless it is dropped in water or solidifies before it touches something (e.g. a lava bomb). Lava bombs have a very typical spindle shape, and being volcanic ejecta, they also are full of gas pockets. Your rock does not have any of the hallmarks of a lava bomb. Even if this was some sort of spatter bomb that landed in water, it would have a typical spindle shape and should still have vesicles (gas pockets). The overall rounding on this looks much more like it is the result of river or ocean tumbling. The little pockmarks are a type of weathering pattern where weathering initially takes advantage of a small spot on the surface of the rock (due to salt, fractures, crystal structure, differential cementation, etc.). Once the weathering starts on a spot, there is now more surface area available. Progressive weathering deepens the pit as the surface area grows.

The greenish one may be chrysoprase - a greenish variety of agate. Any agate variety can scratch glass.

I would have been tickled pink with the IHP, but with all the silvers and nice selection of artifacts to go with it… Wow!

From the manual of mineralogy (Klein and Hurlbut, 20th edition): “Sepiolite (meerschaum), a hydrous magnesium silicate, is a claylike, secondary mineral associated with serpentine. It is used in the manufacture of meerschaum pipes.” Chrysotile: monoclinic, SG 2.5-6, H 4, index of refraction 1.55, Fibrous variety of serpentine; “white asbestos” Sepiolite: orthorhombic, SG 2.0, H 2-2.5, index of refraction 1.52, meerschaum With a hardness 2.5 or less, you should be able to scratch sepiolite with your fingernail. With a hardness of four, you should be able to scratch a copper penny (pre-1982) with chrysotile.

Great find! I would keep all the items together just for the story value. It would be even more mind blowing if you could find part of the chain or other trinkets which went with it. I bet this brings you a smile for years to come!

The last picture shows it has a granular composition. I was thinking quartzite or limestone. The lack of reaction to acid and ability to scratch glass rules out limestone. So, I am thinking it is quartzite.

Augen is German for eye. Looking at your rock you can see how it came by that name.

Bear in mind also, there is some variability in visual color of many crystal species (streak color is a different issue). Also, the color of a translucent or transparent crystal inside a vug while the crystal is sitting on a host rock will appear to be darker than if the crystal is all by itself with a light all around it. The reddish crystals are hard to make out much detail in the pictures. Are the reddish crystals more in the form of pillars or prisms, or more in the form of multi faceted balls?

I concur. Realgar and orpiment deposits tend to easily stir up dust when handled. You don’t want to breathe it. Handle with care. In addition, the grey material with cubic crystals looks like galena - which is lead sulfide. Nice little crystal deposits though.

I may be off topic here, but I travelled over Top of the World Highway once. Aside from the beautiful sights, I always get a little smile when I remember how Chicken, Alaska was named. Ptarmigan were plentiful but nobody could spell it. So the residents named it Chicken instead. 😊 Beautiful sights up there - harsh winters, but beautiful sights.

Aluminum is paramagnetic and has a density of 2.7 g/cm3.

OK, that density changes the equation a bit. Checking…

Guten Tag! My Deutsch is a bit rusty, but I think there was an error in translation. Instead of using my telephone with it I think the translator program meant to say you found out. I also think you meant that as a statement rather than a question. Aren’t translators wonderful? I am not finding any paramagnetic element which fits the data. All the paramagnetic elements I checked are either too hard, to dense, too reactive with air or water, too light, or don’t occur naturally in the elemental state. It is possible it has impurities, as elemental iron and iron (III) are paramagnetic. Now, if you meant to say it is weakly magnetic rather than paramagnetic, then galena can be weakly magnetic due to iron ore impurities.

I am thinking it’s a little too heavy for aluminum. Aluminum would have a specific gravity around 2.7. A chunk of aluminum that size shouldn’t even weigh an ounce. The black oxidation on silver crossed my mind. However, Lake Constance (Bodensee) is one of the larger freshwater lakes in Europe. So without the salt, silver shouldn’t oxidize as rapidly. Platinum is harder and would not be scratched by a knife blade. However, platinum ore would be about the same density as silver. But, platinum nuggets that size are as rare as hens teeth. I am thinking the streak color looks a little on the darkish grey side. That could just be the photograph and lighting. But, I am leaning towards galena right now. However, I would like to have a better idea of hardness and density before deciding.

OK, so the hardness is 5.5 or less. Can you scratch it with a copper penny or your fingernail? if it leaves a color other than steel gray on an unglazed porcelain tile, that would be very diagnostic. I assume that weight is avoirdupois and not Troy? If you can immerse it in a calibrated tube and get the volume and then re-weigh it in grams or grains, that would allow a calculation of density or specific gravity. At a guess, about 3” x 0.5” x 0.25” x 2.54 cubed cm3/in3 equals about 6.15 cm³. 1.8 ounces times 28.3495 g/ ounce equals about 51 g which then works out too about 8.3 g/cm³. Silver would be about 10.5, galena (lead ore) is about 7.5. My density estimation could be way off. But if you can scratch it with your fingernail, then it has a hardness of 2.5 or less. Silver and lead both fit this hardness. Silver will be a more silver white streak whereas lead will be a lead gray streak on a porcelain tile (unglazed). Depending on the actual density or specific gravity and hardness, there are a couple other options.

How big is it? The right size to be comfortably held in one hand? The color banding makes me think it might be a piece of gneiss. Such marks could be a form of chatter mark from a glacier. They all are perpendicular to the grain of the rock. I am not a flint knapper, but my knee jerk reaction is you might want to sharpen with the grain? One of the marks (second from right) appears to extend as a longer fracture into the rock. This suggests the feature may be pressure-derived. There appears to be a lighter colored layer on that side of the stone. All the marks are contained in that lighter layer except the deeper fracture mentioned above. I can imagine sharpening activities might dislodge grains of a sharpening stone which would result in unevenness on one side of a slot. But, some of those slots appear to be curved. That should not result from sharpening. So, my initial opinion is the marks may originally have been naturally occurring. Could some of the straighter marks have been utilized by an opportunist to sharpen? Possibly. I am a geologist, not an artifacts expert. You might want to take my opinion and ask an artifacts expert at a local university. Any flint knappers want to chime in here?

Does it feel relatively heavy, average or light? Do you know the hardness range? Can you scratch it with a fingernail, a copper penny (1981 or older), a modern nail, a pocket-knife blade or a piece of glass? What is the size of the specimen? If you scrape it on an unglazed piece of porcelain, does it leave a color? Do you know the general area where this was found? There are a lot of silvery grey minerals, metals, and metalloids. The above information will help narrow down the options.

Yep, the new pics definitely look like an agate layer on the surface of void areas. When water migrates through pore spaces of a rock, it is under higher pressure and can hold more minerals in solution. When the water enters a void, the pressure drops and the water cannot hold as much mineral content. So, some minerals precipitate on the surface of the voids.

Can it scratch glass? If you put some acid on it (like 0.1 molar hydrochloric acid), does it fizz vigorously or at least produce some bubbles?

It is a little hard to tell from the single picture the composition of the matrix. If it is naturally occurring, then my initial reaction is your “bubbling glass” may be a layer of botryoidal agate. If a corner of that layer can scratch glass, that would support this theory.

Man, somebody break open a coin star machine?😆

Entrances and exits, wooden porches or decks, alongside driveways where people get in and out of cars, and back fence lines. If you find a suspect out house, check around it and in a line to the back of the house. Old tree stumps present the possibility of rope and tire swings, or shade for picnics. I realize old maps won’t necessarily give all this information. But if you know the layout of the road in relation to the house, you can get an idea of front versus back (outhouses in back), and where a side driveway might have been. Also, older houses didn’t have air-conditioning so front porches (and decks) were a high traffic area for keeping cool and talking to neighbors. Probably a lot of nails but also the odd coin which slipped through the boards. Do you have a recovery speed control on your detector? I also like to have a cow magnet in my trowel handle for quickly locating the odd nail. Depending on your capacity for tedium, you may want to take small bites out of the trash areas and then go relax in other areas. Of course, if you find a couple good targets buried in the trash, that can ratchet up your tolerance for the racket. Good luck, and post some finds here!

Silicon also has a black streak and a hardness of around 6.5-7. Part of the issue here may be your streak plate. Make sure you use an unglazed porcelain tile. Scratch resistant porcelain tile should have a hardness of at least 7. Non scratch resistant porcelain tile can be as soft as 4. You may need to test your tile to verify it is 7 or higher. Then, you said the rock would shatter a porcelain tile. I may be drawing a wrong conclusion from that statement. Many people mistake hardness and toughness. You only need to “draw” on the tile (like with chalk) just hard enough to leave a streak. Pounding and grinding are counter-productive here. Also, if this rock is harder than your bit, and drilling did not “bother” the rock, then the “grounds” from drilling may have been dust off your bit. If so, the lack of a smear does not mean the rock lacks a streak color. I am not familiar with drill bit hardness ratings. How does your 5.5-6 mach rating equate to the Mohs scale?

Of course, if you are really lucky, maybe it is sperrylite. That would be harder than galena, and with a hardness of 6 to 7 could blunt your drill bit. However, that would have a fairly high specific gravity. I think jasong is on to something with the silicon call, though. But, if your specific gravity comes back over 10…

Have you tried a streak test, or is it harder than a porcelain tile? What color were the cuttings when you drilled it? Can you grind and polish a small window? The fact it conducts heat/electricity poorly makes me think it is likely more mineral in composition, and less likely elemental metal. Galena and massive stibnite would both be relatively soft and would leave a streak. Hematite would be harder, but will still leave a streak.