Pumicelady 0 Posted September 30, 2020 Share Posted September 30, 2020 Hi all I found this on the south toutle river in wa. I think or the area. Thought was wood but scratches metallic on outside ,non magnetic, streak is blue/gray cuts into plate. Weighs 443.8 grams hardness 5 to 6 smooth greasy feel. Thanks in advance. Quote Link to post Share on other sites
Morlock 1,765 Posted September 30, 2020 Share Posted September 30, 2020 1 hour ago, Pumicelady said: Hi all I found this on the south toutle river in wa. I think or the area. Thought was wood but scratches metallic on outside ,non magnetic, streak is blue/gray cuts into plate. Weighs 443.8 grams hardness 5 to 6 smooth greasy feel. Thanks in advance. My first impression is basalt. I see flow lines and it does streak gray at times. I'm sure others will chime in. Quote Link to post Share on other sites
4meter 201 Posted September 30, 2020 Share Posted September 30, 2020 I think it is a sandstone with desert varnish on the outside. The "varnish" has been mechanically worn off producing the "tiger strips" pattern. Neat find! Desert varnish = a chemical weathering process that produces a dark "rind" on the outside of a rock, exposed to a desert/semi desert environment. Quote Link to post Share on other sites
Haderly 99 Posted October 2, 2020 Share Posted October 2, 2020 On 9/30/2020 at 9:28 AM, 4meter said: I think it is a sandstone with desert varnish on the outside. The "varnish" has been mechanically worn off producing the "tiger strips" pattern. Neat find! Desert varnish = a chemical weathering process that produces a dark "rind" on the outside of a rock, exposed to a desert/semi desert environment. Definitely not found in the correct environment for desert varnish and being found in an active river would obliterate desert varnish. Could have an oxidation rind but I would not wager on it. Based on the geology of the area it is likely an odd ball metamorphic/igneous rock. 1 Quote Link to post Share on other sites
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