Eucryptite
Eucryptite is a lithium bearing aluminium silicate mineral with formula LiAlSiO4. It crystallizes in the trigonal - rhombohedral crystal system. It typically occurs as granular to massive in form and may pseudomorphically replace spodumene. It has a brittle to conchoidal fracture and indistinct cleavage. It is transparent to translucent and varies from colorless to white to brown. It has a Mohs hardness of 6.5 and a specific gravity of 2.67. Optically it is uniaxial positive with refractive index values of nω = 1.570 - 1.573 and nε = 1.583 - 1.587.
Its typical occurrence is in lithium-rich pegmatites in association with albite, spodumene, petalite, amblygonite, lepidolite and quartz.
It occurs as a secondary alteration product of spodumene. It was first described in 1880 for an occurrence at its type locality, Branchville, Connecticut. Its name was from the Greek for well concealed, for its typical occurrence embedded in albite.
References
Podcasts:
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by U2
Acrobat
by: U2Don't believe what you hear
Don't believe what you see
If you just close your eyes
You can feel the enemy
When I first met you girl
You had fire in your soul
What happened your face
Of melting in snow
Now it looks like this
And you can swallow
Or you can spit
You can throw it up
Or choke on it
And you can dream
So dream out loud
You know that your time is coming 'round
So don't let the bastards grind you down
No, nothing makes sense
Nothing seems to fit
I know you'd hit out
If you only knew who to hit
And I'd join the movement
If there was one I could believe in
Yeah I'd break bread and wine
If there was a church I could receive in
'cause I need it now
To take a cup
To fill it up
To drink it slow
I can't let you go
I must be an acrobat
To talk like this
And act like that
And you can dream
So dream out loud
And don't let the bastards grind you down
Oh, it hurts baby
(What are we going to do now it's all been said)
(No new ideas in the house and every book has been read)
And I must be an acrobat
To talk like this
And act like that
And you can dream
So dream out loud
And you can find
Your own way out
You can build
And I can will
And you can call
I can't wait until
You can stash
And you can seize
In dreams begin
Responsibilities
And I can love
And I can love
And I know that the tide is turning 'round