Strictly defined, elementals are creatures who have not yet created the soul; in other words, they have consciousness ("anima," raw, unformed soul) as given by nature, and have evolved mechanically through the lower kingdoms. Their physical bodies are the minerals, plants, animals, and humanoids (intellectual animals); internally they have the appearance of people (gnomes, sprites, elves, fairies, mermaids, dwarves). However, in common usage the term elementals refers to the creatures of the three lower kingdoms: mineral, plant and animal, and out of politeness we call the intellectual animals "human," even though they have not become human yet.
"Just as visible Nature is populated by an infinite number of living creatures, so, according to Paracelsus, the invisible, spiritual counterpart of visible Nature (composed of the tenuous principles of the visible elements) is inhabited by a host of peculiar beings, to whom he has given the name elementals, and which have later been termed the Nature spirits. Paracelsus divided these people of the elements into four distinct groups, which he called gnomes, undines, sylphs, and salamanders. He taught that they were really living entities, many resembling human beings in shape, and inhabiting worlds of their own, unknown to man because his undeveloped senses were incapable of functioning beyond the limitations of the grosser elements. The civilizations of Greece, Rome, Egypt, China, and India believed implicitly in satyrs, sprites, and goblins. They peopled the sea with mermaids, the rivers and fountains with nymphs, the air with fairies, the fire with Lares and Penates, and the earth with fauns, dryads, and hamadryads. These Nature spirits were held in the highest esteem, and propitiatory offerings were made to them. Occasionally, as the result of atmospheric conditions or the peculiar sensitiveness of the devotee, they became visible." —Manly P. Hall, The Secret Teachings of All Ages
“Each elemental of Nature represents certain powers of the blessed goddess mother of the world. Thus, whosoever knows how to handle the powers of nature that are enclosed within each herb, within each root and each tree, is the only one who can be a true magician and doctor. Thought is a great force, yet everything is dual in creation. Thus, if we want to make perceptible any hidden intention, a physical instrument that serves as the clothing for that idea is necessary. This instrument is the plant that corresponds to our intention. Only the one who knows the secret of commanding the elementals of plants can be a magician.” —Samael Aun Weor, Esoteric Medicine and Practical Magic
"In the times of King Arthur and the Knights of the Round Table, elementals of Nature were manifest everywhere, deeply penetrating our physical atmosphere. Many are the tales of elves, leprechauns and fairies, which still abound in green Erin, Ireland. Unfortunately, all these things of innocence, all this beauty from the soul of the Earth, is no longer perceived by humanity. This is due to the intellectual scoundrel’s pedantries and the animal ego’s excessive development." - Samael Aun Weor, The Great Rebellion