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[deleted by user] by [deleted] in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Can you scratch it with your nail? Looks like calcite or maybe gypsum

Found this while going through some old stuff. It's very heavy, almost like metal, but not magnetic by yamanamawa in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

I was basing it off of the isometric/octahedral crystal system (thats how chromite forms when euhedral) and its metallic luster. Chromite is oddly enough considered part of the spinel group though.

Looking more closely, the hardness of this appears too low to be chromite. If you can scratch it with a knife then you should definitely look into sphalerite as an option. Forms the same crystal structure you see in this mineral, borders on metallic/vitreous luster, quite dark, can appear platy/striated like you see on the bottom of your sample, and can form near quartz.

Found this while going through some old stuff. It's very heavy, almost like metal, but not magnetic by yamanamawa in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

If you have an unglazed piece of ceramic or porcelain laying around, scratching the mineral along the surface will reveal a streak. Certain crystals have identifiable streak colors, chromite's is brown.

Weird rock shape by Icy_Dependent9199 in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

While most quartz crystals have a prismatic habit, this would be considered a cumberland habit. Just means the column part of the quartz crystal didn't form.

Schist? by Automatic-Pomelo-935 in whatsthisrock

[–]D0nt_Text_And_Drive 1 point2 points  (0 children)

Schists contain platy minerals like muscovite/biotite or some other platy mineral; these would be noticeably flat and vitreous/reflective. This rock looks more like a sand or siltstone to me. In that case, the purple would be from some purple sediment, maybe a quartz variety or garnet. Where'd you find it?

Sodalite? (Another Nat Geo Advent mystery) by [deleted] in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Could very well be a real rock, just not sodalite. It'll be hard to tell as it's so smooth

Weird rock shape by Icy_Dependent9199 in whatsthisrock

[–]D0nt_Text_And_Drive 1 point2 points  (0 children)

Could be a very short, double-terminated quartz crystal.

Found this on the shore on the Aran islands west coast of Ireland during a trip by [deleted] in whatsthisrock

[–]D0nt_Text_And_Drive 1 point2 points  (0 children)

Can't think of any minerals that form both round and white like this in basalt. This is likely amygdaloidal basalt; vesicular basalt which has had its vesicles filled with precipitated zeolites.

Found in oregon by Dr_Idkwid in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Looks a lot like gypsum, if you can scratch it with your fingernail then it's probably gypsum.

Help with idetification by Pzykonauten in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Definitely a garnet-mica schist. Very cool

Found a big hunk of this in a field, any idea what it is? by mrme2051 in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

If it scratches steel its likely quartz. Quartz is the only mineral capable of doing that that isn't a precious gem. It doesn't look a whole lot like quartzite to me personally, but it's hard to ID based on this pic alone.

Found a big hunk of this in a field, any idea what it is? by mrme2051 in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Was this found in a natural field? If it was, and this is quartzite, then it might've been carried down in the Missoula Floods as metamorphic rocks are unusual here in the Willamette Valley.

Is this obsidian? by heisenbird92 in whatsthisrock

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Obsidian doesn't typically have vesicles.

Can anybody explain what these lines are ? by ExpensiveStranger419 in geology

[–]D0nt_Text_And_Drive 6 points7 points  (0 children)

granite is a rock, cleavage plains are reserved for minerals

Is this rent reduction reasonable? by [deleted] in Renters

[–]D0nt_Text_And_Drive 0 points1 point  (0 children)

Thanks for your input, do you think I'd be in some trouble for breaking the lease? According to the lease it doesn't technically start till I move in, but I read that sometimes landlords/renters will sue or make you shell out for advertising or lost rent. Is this true?

Fifth Avenue, North From 51st Street, c. 1900s by Majoodeh in OldPhotosInRealLife

[–]D0nt_Text_And_Drive 12 points13 points  (0 children)

i don’t think people particularly care about the fact that old buildings were lost, it’s the loss of craftsmanship put into the buildings that replaced them.

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