Discover and read the best of Twitter Threads about #Calcite

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#MinCup2019 semifinals at @PMEUBC:

#Quartz: from Arkansas, USA
Amethyst: from Anahi Mine, Bolivia

#Calcite: detailed description of how 12% by mass is atmospheric carbon from 495 million years ago, what that tells us about ancient worlds, & how carbon is captured into crystal Large white hexagonal crystalsLarge purple hexagonal crystalsLarge blob of yellow trapezoidal crystals
If you can’t grow it, you mine it.

I’ve seen plenty of #MinCup2019 arguments that #quartz is in smartphones, but it doesn’t seem like many realize #calcite. Both semifinalists are in your phone display screen.
#Calcite & #quartz are battling it out in the semifinals of #MinCup2019. Quartz took a strong early lead, but calcite is creeping closer.

Quartz has never won despite the entire competition being founded to promote it.

I voted calcite.
Read 3 tweets
I’m totally amused how #quartz is catering the pity vote. All of #MinCup was created to make it feel special, yet every year other minerals win. Poor quartz.

Meanwhile #calcite is both fun & a climate indicator.
#Calcite is a mineral with neat optical properties, fizzes with acid, flags your attention when you stumble on to an ancient sea floor in the mountains, was a critical plot point for the premiere of #Stargate #SGU, and tracks climate.

But I lost a bet.
Whoo #quartz. Screenshot of a Stargate team in a desert investigating geology
So. #Quartz.

It’s most of Earth’s crust. If you’re only learning one mineral, quartz is a good default guess.

I can’t help with ID more than”uh, it’s hard?” unless it happens to be a pointy crystal, but I’ve never found those in the wild. It’s the white bits of granite. Large quartz crystal with plastic dinosaur
Read 10 tweets
We’re in the semi-finals of #MinCup2019 & I Have Opinions.

This is the year of #ClimateChange, the year we hit the tipping point of enough people caring to finally get to the large-scale hard work.

Our winner has to be ice or #calcite (tomorrow’s semi-finalist). #IceMin
#Olivine is a good mineral, a former 2017 #MinCup champion & one I campaigned for in past years.

It has so many cool quirks, including making green sand (!!). But it already won before.
Every year, people are startled to learn #IceMin is a mineral!

It’s naturally occurring, solid, has definite composition, & a repeating crystalline structure. As long as you find it in the wild, it checks every box.

Want it solid at room temperature? Ice VII trapped in diamond.
Read 5 tweets
Today’s #MinCup2019 is a face off between Very Interesting Properties. A translucent rock on a postcard creating a magnifying optical effect next to a small jar of black sand with a magnet stuck to it
Lots of minerals have neat optical effects, but #Ulexite is a bit different.

Light doesn’t pass straight through, like with #quartz or #halite (salt), nor does it have the birefringence of #calcite. Instead it’s a mineral of natural fibre optic channels transmitting light. Top view of the listed minerals on a postcardSide view of the same scene
#Ulexite grows as a bundle of fibers, each of which totally internally reflects light. It’s the same basic optics behind why diamond is sparkly.
Read 7 tweets

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