There are lots of varieties of Calathea, but the most common Has luscious dark green leaves that have scalloped edges and silver brushmarks on the top of the leaves and a lovely shade of burgundy purple underneath.
Varieties
Recommendations for growing success:
Light: Partial shade to indirect sunlight
Soil: Use well draining soil
Humidity: This plant loves humidity so consider a pebble tray or humidifier
Watering: In warmer seasons keep soil moist at all times, in the winter allow the top layer of soil to dry out between watering