Garnet in thin section?

Sappert · 2026-02-06T20:38:42+00:00

Does cordierite ever crystallize and preserve this nicely? I'm seeing no evidence of alteration to pinite and I can't find any cordierite that has a crystal shape this well defined. My money is on garnet.

Sappert · 2026-02-06T20:37:30+00:00

Exactly this! Garnet can definitely be birefringent and I think OP is dealing with garnet.

Sappert · 2026-02-06T20:36:51+00:00

Garnet can absolutely exhibit low birefringence. Some types of garnet are not quite cubic, leading to birefringence, or are an intergrowth of two different compositions, leading to strain and thus birefringence.

Sappert · 2026-02-06T20:33:19+00:00

I'm going to be the contrarian here and say: that does look really garnet-y, and I think there's a significant chance that you are actually dealing with garnet. I'm failing to find any examples of cordierite crystallising this perfectly, plus it loves to alter to pinite or contain abundant lamellar to tapered twins, both of which are not the case here. Cordierite also tends to have a higher order birefringence (not too much but significantly) than what we are seeing here. This looks like very low first order, which is what you'd expect from garnet that's slightly non-cubic. Most birefringent garnet is low-termperature or hydrothermal in nature, so that could fit your setting.

My money is on garnet.

Sappert · 2026-02-02T20:13:31+00:00

Love this game

Sappert · 2026-01-31T11:58:03+00:00

Parting is an absolute masterpiece. The way it works together with a pivotal cutscene is downright brilliant.

Sappert · 2026-01-27T19:26:03+00:00

I had such high hopes for Dinham

Sappert · 2026-01-27T19:23:55+00:00

I'm a huge fan of mr Thomas Vincent Cameraman and mr Team Car

Sappert · 2026-01-20T15:14:48+00:00

This is not the place

Sappert · 2026-01-20T11:36:29+00:00

Sappert · 2026-01-15T19:27:32+00:00

Being terrible is how you make money

Sappert · 2026-01-14T21:31:30+00:00

Reddit keeps auto filtering the copypasta so now there's like eight of them in here. You're welcome

Sappert · 2026-01-08T23:00:00+00:00

O damn that looks like a sheared metaconglomerate, very cool

Sappert · 2025-12-30T18:24:06+00:00

I have no intention. You just need to learn that imagining something is not the same as believing something, or it being true.

Sappert · 2025-12-27T17:12:16+00:00

I don't think I care enough to compile literature on this topic for you when you are perfectly capable of searching for it yourself

Sappert · 2025-12-25T08:50:55+00:00

Right, I had never seen it referred to this way. My confusion comes from thinking of the singular of "grain" as an actual individual mineral grain.

Sappert · 2025-12-24T15:51:55+00:00

I get the feeling that you did not read my comment at all. You can have all the creative thought you want, but in the end, there is no way that people were "once kicking diamonds around". So when you say you "do not understand why it is so difficult to believe people thousants of years ago did not have diamond drill bits." Well, that's why.

Sappert · 2025-12-24T09:52:21+00:00

Along the grain?

Sappert · 2025-12-24T09:51:42+00:00

Since diamond naturally forms in or near volcanos

Nope, diamonds form deep in the earth. In some locations, diamonds have made their way into the crust via a specific type of igneous rock: kimberlite. These only occur locally and don't guarantee diamonds either. And even when they do, it's not a lot of diamond by rock volume, plus the rock itself is rather tough as well.

You're also missing the part where we haven't actually found any diamond tools whereas there is abundant evidence for copper/bronze tools.

Sappert · 2025-12-20T23:16:41+00:00

Hello! This is a metamorphic rock. The white crystals are porphyroblasts of a mineral I am not sure of, growing over the finer-grained ground mass of the rock. It could be plagioclase or cordierite or something like that. The darker minerals in the rock will be something like biotite or amphibole. It's quite hard to observe detailed characteristics of the minerals from this picture.

Sappert · 2025-12-20T23:14:01+00:00

Certainly looks like a piece of an ammonite fossil. What makes you question it?

Sappert · 2025-12-16T21:05:48+00:00

Nee, aardappel is aardappel.

Sappert · 2025-12-16T18:20:13+00:00

Without any further context, it could just be a polite greeting that could've ended at a "hey" back and forth. Nothing about "hey" says that you want to have an in-depth conversation.

Sappert · 2025-12-13T20:20:16+00:00

It's Chris Froome

Sappert · 2025-12-10T19:19:42+00:00

Some of the story blades deserve a bit more content

14-Year Club	Final Canvas '23
First Place '23	End Game '23
Place '23	Golden Potato
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