When a drug company in the 80s scaled up production they accidentally created seed crystals that spread around the entire Earth's atmosphere that prevented other companies from manufacturing a generic drug without it attaching to the seeds and converting to the patented drug.

https://en.wikipedia.org/wiki/Disappearing_polymorph#Paroxetine_hydrochloride

Ancient Egypt was ancient before it ended. The time when Cleopatra ruled is about as close to today as it was to the first pyramids.

You know how geese fly in a “v” shaped pattern in the sky? One side of the “v” is usually longer than the other. The reason for that is that there’s more geese on that side.

Most male cats, when investigating something with a paw, will use the left paw.

Bedsheet thread counts have been artificially inflated for years by the shifty linen companies counting individual fibers that the threads consist of as threads themselves. It’s become a meaningless number, since there is zero regulation. If you want a nice thick heavy cloth, GSM is the number you want, but most companies won’t share this (looking at you, The Company Store) because they obviously don’t want you to know how thin and flimsy their products really are before you buy them.

The dot above the letter i is called a tittle.

If you catch a frog in between your hands and quickly flip it around, you can get the frog into a kind of paralyzed state called 'tonic immobility'.

Here is a photo from Wikipedia:

OK, well, many years ago I was very interested in this phenomenon and decided to look into the literature.

I found a paper from 1928 titled "On The Mechanism of Tonic Immobility in Vertebrates" written by Hudson Hoagland (PDF link).

In this paper, the author describes contraptions he used to analyze the small movement (or lack of movement) in animals while in this state. They look kind of like torture devices:

OK, but, that's still not it.... The obscure fact is found in the first footnote of that paper, on page #2:

Apparently this or a similar effect can be observed in humans too?! In this paper, the author himself claims to have done this and that it works! I tried to locate more recent resources describing this phenomenon in humans but I could not find them... Is this actually possible? If so, why is this not better documented? Or, maybe it is better documented but understood as a different type of reflex today? Not sure.

There are more hydrogen atom in a single molecule of water than there are star in the entire solar system.

Not obscure but apparently a lot of people aren't aware that sheep don't have top teeth in front.

&

This symbol, the ampersand, used to have equal status with letters of the alphabet and was stuck at the end after Z.

That's how it got its name. People would say "X,Y,Z, and, per se, And". (And "sort of" an and). Thus, "And per se And" became Ampersand.

Fun fact, you can, in fact, make sourdough with the yeast from a yeast infection, and bake with it.

Chinese scientists worked to create the "humanzee," a human-chimpanzee hybrid in the '60s. Female chimpanzees were impregnated with human sperm. The experiment was cut short by the Cultural Revolution - the scientists were sent to labor camps and a three-months pregnant chimpanzee died of neglect. The Soviets attempted a similar program in the '20s.

Diamonds aren't stable and will eventually, over billions of years, decompose from their cubic molecular structure to carbon's more stable form, graphite, which has a hexagonal molecular structure.

Oh, here's another good gemstone related one!

Amethyst and citrine are both quartz varieties, and if the color source happens to be from traces of iron in the crystal lattice, one can be turned into the other. Heating amethyst can make citrine, and irradiating citrine can turn it into amethyst. This is because the only actual difference between the two is the valiance level of a specific election in the iron atom giving the stone its color.