Smaragdine means bright green, like an emerald.
Smaragdine is a fancy word for green, like the color of a shiny jewel.
Examples:
The forest was smaragdine and full of life.
She wore a smaragdine dress to the party.
The smaragdine frog hopped through the grass.
The dragon's scales were smaragdine and sparkly.
The smaragdine fields stretched as far as the eye could see.
The queen's crown was smaragdine and beautiful.