
Okay, so it's QUARTZ.
The Big Bang Theory Season 12, Episode 2

Oh, you forgot your QUARTZ.
The Big Bang Theory Season 7, Episode 13

What do we know
about QUARTZ?
The Big Bang Theory Season 12, Episode 2

And that stone in front--
I bet it's QUARTZ.
The Big Bang Theory Season 12, Episode 2

It's a silicon dioxide crystal,
otherwise known as QUARTZ.
The Big Bang Theory Season 12, Episode 2