What do you call the word used in prose to describe the surroundings to make prose richer?

There is a word in English which is used to describe the technique used by authors where they describe the surroundings (like sight, sounds, smells, etc.) to make the scene more rich.

Like "there was fresh sand between the driveway paving stones and a diminutive sapling on the lawn" to describe that the house is new.

What is that word?

Imagery

The type of imagery from your example ("there was fresh sand between the driveway paving stones and a diminutive sapling on the lawn") would be visual. You're attempting to paint a picture in the reader's mind to describe the house as being new.

You can use imagery to appeal to any of your reader's senses. Attempting to describe a particular smell would be one...

The acrid stench of burnt hair lingered in the air.

EDIT: Wikipedia has a decent description of sensory imagery.

Could it be descriptive?