What effect does imagery create in the Oscar Wilde's works, such as The Picture of Dorian Gray?
The use of different names of plants, precious stones, and other items is a stylistic device often chosen by writers of the aesthetic movement in order to produce strong and beautiful imagery.
Wilde's use of this type of language is what makes the scene so clearly-illustrated in The Picture of Dorian Gray. The imagery not only emphasizes the beauty of the collections that Dorian has taken to gather together; it also helps us understand the extent to which Dorian has decided to follow the new Hedonism of which Lord Henry speaks of all the time.
In chapter XI, when Lord Henry expresses to Dorian the way that this new Hedonism aims to seek new sensations in everything, he also appeals to how by "everything" he means "everything and anything new and beautiful". In typical Wildean fashion, this would be a euphemism for things that are moral AND immoral, alike.
Hence, we find Dorian aiming to attain everything he finds pleasurable and keeping it for himself as he indulges in a form of never-ending gluttony. In this gluttony, his aim is to collect "everything and anything" which gives him a sense of beauty, as if in aims to build an artificial world of mere aesthetic value:
It was the creation of such worlds as these that seemed to Dorian Gray to be the true object, or amongst the true objects, of life;
In his quest, Dorian's collections transform from interesting, to sublime, to excessive, demonstrating how his hunger for beauty must have an underlying cause perhaps even caused by evil, itself...or else, by this mysterious Hedonism that Dorian, himself, cannot even grasp in its entirety:
...he felt a curious delight in the thought that Art like Nature, has her monsters—
He would often spend a whole day settling and resettling in their cases the various stones that he had collected, such as the olive-green chrysoberyl that turns red by lamplight, the cymophane with its wire-like line of silver, the pistachio-colored peridot, rose-pink and wine-yellow tpoazes, carbuncles of fiery scarlet with tremulous four-rayed stars, flame-red cinnamon-stones, orange and violet spinels and amethysts with their alternate layers of ruby and sapphire. He loved the red gold of the sunstone, and the moonstone's pearly whiteness, and the broken rainbow of the milky opal.
From these words we obtain the rich and intense imagery and the sound of strange, new, and beautiful words, that Wilde's aesthetic generation (1870's-1880's) aims to reach in all forms of art. These descriptive devices are a consequence of a generation of artists which supersede Art over Nature, for Art is meant to represent true and sincere human emotion: one that we can control, or that can be controlled, by either our angels, or our demons.