enter image description hereThis rock is 2 3/8", weighs 71 grams has a density of 2.958,I tested the density a few times and its always 2.958,enter image description here has a hardness of 6-7 almost clear streak test, I tested the streak again and I would say its clear and no color.Found this rock among cobble stones in Roscommon Ireland]3]3http://www.johnbetts-fineminerals.com/jhbnyc/articles/specific_gravity.htm

  • $\begingroup$ i upvote your question simply because it have some information in it. $\endgroup$ – trond hansen Feb 8 '19 at 14:56

Your rock is likely to a metamorphic rock: metabasalt (metamorphosed basalt), ophiolite, or Amphibolite. Most basaltic rock when cut will show vugs or void spaces. Typical metamorphic rocks have few open voids due to the pressure and temperature changes which close these voids as the rocks are transformed. Texture of your stone suggests it is more likely to be metamorphic than basalt.

Metamorphic rocks are found in Ireland (see geological if Irealend).

Also, my experience with cutting and polishing rocks is most basaltic rocks (except for obsidian: volcanic glass) do not polish well because of the tiny voids.

  • $\begingroup$ Thank you Gary Kindel for sharing your knowledge and helping identify this rock,the link you shared is very interesting and detailed $\endgroup$ – Dave Feb 9 '19 at 15:51
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    $\begingroup$ Could also be just metasediment at around greenschist facies (chlorite, epidote, etc) $\endgroup$ – Gimelist Feb 10 '19 at 23:30

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