Simile
Flint
An emerald is as green as grass, A ruby as red as blood;
A sapphire shines as blue as heaven; A flint lies in the mud.A diamond is a brilliant stone, To catch the world's desire; An opal holds a fiery spark; But a flint holds a fire.
-Christina Rossetti
A simile is a figure of speech involving the comparison of one thing with another thing of a different kind, used to make a description more emphatic or vivid.