enter image description hereenter image description here This rock was found in kephalonia Greece, on a beach in lassi. The rock is black in colour, smooth with thumb like prints, very metallic smell and very slightly magnetic. We took this rock to oxford museum of natural history to be seen by a mineralogist. We received a very confused letter back from the mineralogist, he has no definitive answer as to what this specimen is, he said it has iron like features but was not certain. Embedded in this rock is a white cylinder like object, the mineralogist stated in the letter; “How you end up with a plastic pipe in the specimen I don’t know, slag or iron material would be incredibly hot and would melt the pipe therefore is it plastic? you have stumped me”. The rock itself has to have been hot enough to melt through the “pipe” as you can see in the pictures attached. Please could someone help us know what this is and how this has happened? Thankyou !

The rock shown weighs 131 grams, is very hard, and leaves a greyish streak.

  • $\begingroup$ please give more details,weight-hardness-streak test.please take a look here earthscience.meta.stackexchange.com/questions/124/… $\endgroup$ – trond hansen Apr 21 '19 at 5:46
  • $\begingroup$ It weighs 131 grams, it’s very hard and leaves a greyish streak. $\endgroup$ – Jordan Presley Apr 21 '19 at 8:25
  • $\begingroup$ Is the pipe actually plastic? $\endgroup$ – Gimelist Apr 21 '19 at 12:19
  • $\begingroup$ The pipe isn’t plastic, it’s hard to say what it could be, it’s very very tough, the best way I could describe it is it feels ceramic but 10x more tough and it’s not breakable, will not shatter or snap. $\endgroup$ – Jordan Presley Apr 21 '19 at 12:32
  • $\begingroup$ I would say your sample looks to be some form of weathered electrical connector or insulator. Metal molded around and in ceramic is common in industrial electrical equipment. The metal might be more prone to wear and chemical corrosion leaving the ceramic insulator in better condition. $\endgroup$ – user824 Apr 24 '19 at 17:06

That is 100% a spark plug that has been melted. Without a doubt. Spark Plug Examples

  • $\begingroup$ That's pretty big for a spark plug. $\endgroup$ – Spencer Jun 25 '19 at 22:42
  • $\begingroup$ Heavy duty equipment uses larger spark plugs. Look at it... it's obvious. Huge hunk of melted metal at one end. Small bit of melted metal at the other end. And a WHITE PORCELAIN INSULATOR IN THE MIDDLE! lol. Sorry for shouting, but to question this further is beyond me. I can't help you if you want to question it any more. $\endgroup$ – Rokman Jun 26 '19 at 4:52
  • $\begingroup$ Spark plugs weigh about 50g. I can't find any reference to larger ones. There is no physics reason they need to be larger: 800HP Formula 1 engines use plugs weighing 10.7g. Heavy duty equipment tends to be diesel, which doesn't use spark plugs. $\endgroup$ – Keith McClary Jul 27 '19 at 4:10

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