Discover and read the best of Twitter Threads about #calcite

Most recents (8)

Today #MinCup2020 is a battle of the carbonates.

Reasons to vote #Calcite: Perfect cleavage

Reasons to vote #Malachite: Specimen CC3353 from Copper Crescent in D.R. Congo.

đź“· Crystal Classics Side view of an extremely p...Alternate side view of an e...Top view of an extremely ph...Cut bottom view of an extre...
Q: Lick?
A: Sure, #malachite is safe but boring for a quick taste.

Q: Nibble!
A: Ehhhh, not such a great idea. It’s soft (3.5-4 vs teeth at 5) & copper isn’t exactly a healthy snack.

Q: 🍆?
A: Pls no. While #Calcite bubbles in acid, malachite slowly dissolved into green goop.
Q: PERFECT cleavage? Really?

A: If you SMASHY-SMASHY calcite, it breaks on planes of weakness (cleavage planes) into 6-sided polyhedrons with diamond-shaped faces with 78° & 102° angles.

See:
đź“·: ??? stolen from old textbooks I think??? Calcite Crystal broken into...Calcite crystal and hammer ...
Read 3 tweets
#Malachite is gorgeous & I adorn myself with it regularly, but you're really going to want to vote for ##Lonsdaleite.

It forms in meteor impacts.
...from unusual meteors.

It's named for a #WomenInSTEM.
...from Ireland.
...who worked prison reform.
...after being imprisoned.
Whichever mineral survives will face off against #Calcite in Round 2.

Both calcite & malachite do fun things with acid (bubble; dissolve) and are iconic basic minerals to identify during intro geo lab classes. It'd be a solid, decent thread.

But lonsdaleite is SO WEIRD.
I don’t have the bandwidth to do proper campaign thread until I make it past a few deadlines, but futureYou will appreciate it if you keep #Lonsdalelite in the running until Round 2.
Read 3 tweets
It's 2020, the year where anything can happen.

The #MinCup2020 bracket is sticking to the rules with all official minerals. Voting starts September 1st.

Who will join legends #Olivine (2017), #Garnet (2018), & #IceMin (2019) to be this year's #champion? Bracket reading in order: B...
#MinCup2020 is kicking off quasi-alphabetically in a battle of peacock ore #Bornite vs poisonous red #Cinnabar

Pick your champion, make your arguments, and VOTE!
ROUND 1 MATCH 1 goes to #Cinnabar with a 8% lead over rainbow #Bornite! The same bracket, but with ...
Read 6 tweets
#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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