There are two Judas Priest versions on YouTube.

The "original"

Diamonds & Rust (allegro)

And this one, more in keeping with Joan's

Diamonds & Rust (andante)

I saw an interview once where Joan complimented Judas Priest on their "interpretation"

When she sings the song live now, it says "40 years ago" and tends to end

"If you're offereing and rust,
I'll take the diamonds."