Post by: jmcef on 08/05/2018 23:25:51
i have some stones, found in a beach in europe. they are pretty common in the water as well. they look like a highly corroded piece of metal, but they are stones and not magnetic (so unlikely to be just that)
stones.jpg (265.37 kB . 1664x597 - viewed 6165 times)any info to help identify them would be greatly appreciated
thanks
Post by: Kryptid on 09/05/2018 02:46:23
Post by: jmcef on 09/05/2018 03:00:04
When you see one you would think that its a badly corroded piece of metal, but its a stone so if it was a corroded metal it would just turn into dust.
thanks for any input you might have :)
Post by: Kryptid on 09/05/2018 03:12:41
Here is a list of minerals based on their density. It would work as a good starting point: https://www.engineeringtoolbox.com/mineral-density-d_1555.html (https://www.engineeringtoolbox.com/mineral-density-d_1555.html)
When it comes to the hardness, I guess your next step is to see if the mineral itself can scratch glass or steel. If it can scratch glass, then it should be about the same hardness as glass (5.5 on the Moh's scale). More information can be found here: http://www.oakton.edu/user/4/billtong/eas100lab/hardness.htm (http://www.oakton.edu/user/4/billtong/eas100lab/hardness.htm).
Have you tested the color of the streak yet? Maybe you could also test for fluorescence under a blacklight.
Post by: RD on 09/05/2018 17:07:19
i have some stones ... look like a highly corroded piece of metal, but they are stones ...
Iron stone (https://www.google.com/search?tbm=isch&q=ironstone%2Bmineral) ? ...
Unknown Versus banded-IronStone.jpg (39.89 kB . 773x215 - viewed 5234 times)https://en.wikipedia.org/wiki/Ironstone (https://en.wikipedia.org/wiki/Ironstone)
Post by: jmcef on 09/05/2018 17:14:59
it was gathered from the island of Malta, was found in some lost beach but others can be found in different areas of the island
thx
Post by: chris on 10/05/2018 08:09:13
Post by: guest45734 on 10/05/2018 12:28:10
it was gathered from the island of Malta, was found in some lost beach but others can be found in different areas of the island
The Maltese Islands are made up of 5 different rock types. These are namely; Upper Coralline Limestone, Greensand, Blue Clay, Globigerina Limestone and Lower Coralline Limestone.
How much do the stones weigh?
Post by: chiralSPO on 10/05/2018 14:33:36
If you're willing to do some destructive sampling, I recommend submerging a small stone in vinegar (5% acetic acid). If bubbles begin streaming out, it is probably carbon dioxide, indicating a carbonate rock like limestone (though there are many carbonate minerals). There are ways to confirm that the gas is CO[sub2[/sub]. If it does react vigorously with the vinegar, I recommend letting the reaction go until everything that can dissolve has--there might be some other materials included in the stone.
You could also try putting a stone in liquids such as hydrochloric acid (sold in hardware stores for removing rust stains), bleach (sodium hypochlorite) and lye (sodium hydroxide). You can learn quite a bit about the composition based on what it reacts with/dissolves in and other observations--if it smells like rotting eggs when treated with hydrochloric acid, it probably contains sulfides, if it dissolved in hydrochloric acid or ammonia and produces a colored solution, the stone might contain transition metals like iron (yellow to brown solutions), cobalt (pink/purple/blue) nickel (yellow to green), copper (blue to green) etc.
Post by: jmcef on 10/05/2018 15:11:13
it was gathered from the island of Malta, was found in some lost beach but others can be found in different areas of the island
The Maltese Islands are made up of 5 different rock types. These are namely; Upper Coralline Limestone, Greensand, Blue Clay, Globigerina Limestone and Lower Coralline Limestone.
How much do the stones weigh?
thanks for the message. i am familiar with the Maltese rock types but the stones in questions are nothing related to them. they are found mainly in some beaches (with the other pebbles) so they are pretty hard, the once in the photo can easily stay in the palm of a hand (so we are not talking large rocks)
thanks
Post by: guest45734 on 10/05/2018 16:42:16
i am familiar with the Maltese rock types but the stones in questions are nothing related to them. they are found mainly in some beaches (with the other pebbles) so they are pretty hard, the once in the photo can easily stay in the palm of a hand (so we are not talking large rocks)
Could the rocks be Clinker from old furnaces?
Another possibility is that the stones are Fubarite.
Post by: jmcef on 10/05/2018 17:09:54
Clinker
theirs some distant similarities to some brown Clinker but i think its unlikely because they are found in different remote areas on the island, underwater too, so unlikely of being anything man made - apart from the fact that they are very hard and dense, resembling beach pebbles. at first glance i think they distantly resemble brown meteorites (but they are not, they are not attracted to magnets)
i have always wondered what they are because they are particularly different from the typical pebbles
thanks
Post by: jmcef on 10/05/2018 18:05:01
Post by: Bass on 10/05/2018 18:47:54
Secondary (from weathering) iron oxides are common in many limestone terrains, and most limey rocks contain iron at different concentrations. Common iron carbonate rocks are siderite and ankerite.
Do any of the rocks effervesce (bubble) when you put acid on them? Sometimes you have to scratch or grind down a bit of powder before you get a reaction.
Post by: chris on 10/05/2018 21:39:49
Do any of the rocks effervesce (bubble) when you put acid on them?
Is this to test for limestone?
Post by: jmcef on 11/05/2018 01:04:28
hematite
thanks for the reply, i am aware of iron in milestones but normally they iron in them is brittle - not as dense and sturdy as these rocks.
when put in vinegar theirs some bubbles, but very little and from the surface material on the stone (so i think the bubbles might be unrelated to the material)
Post by: Bass on 15/05/2018 19:17:22
Secondary iron oxides can be brittle and easily broken or crumbled, or can be quite dense- depending on how they formed.