Leśyā is a very subtle level of consciousness, which is in the form of radiations. It is categorized into 6 types - Kṛṣṇa, Nīla, Kāpota, Tejas, Padma and Śukla.
Out of them, the first three leśyās are malevolent and the next three leśyās are benevolent. The benevolent leśyās are bright, smooth and warm. Malevonet leśyās are dark, rough and cold.
The vibrations of malevolent leśyās are responsible for one's indulging in violence, lie, stealing, jealousy, sorrow, hatred and fear.
The vibrations of benevolent leśyās develop soothing feeling such as fearlessness, friendliness, peace, control over the senses, forgiveness etc..
These six leśyās have six colors respectively - black, blue, gray, red, yellow and white. All our bhāvas (emotions) are influenced by the leśyās which transform them in benevolent and molevolent effects. Emotions and thoughts are different states of consciousness. Emotion is more intrinsic than thought and the endocrine system helps in creating it, whereas the thought is related with the nervous system.
Emotions are of two types - auspicious and inauspicious. The colors play vital role in their creation. Leśyās of red, yellow and white colors are the cause purity of emotions.
In the Jain philosophy, leśyā has been described in great detail. To understand this, the following illustration is helpful.
Six friends went into a garden. There they saw a Eugenia Jambolona (Jāmun or black plum) tree ladden with ripe Jāmun fruits. The first friend said, "Let us uproot this tree and eat the Jāmun to our heart's content." The second one said, "What's the use of uprooting the tree? Only cutting the big trunks can serve our purpose." The third one said, "This is also not proper, our purpose can be served only by cutting the smaller branches." The fourth one said, "What's the benefit of cutting the twigs? Only plucking bunches of fruits will do." The fifth one opined, "What we have to do with the bunches? Only plucking of the fruits is enough." The sixth one said seriously, "Why to bother about all this? The quantities of fruits we require are just fallen on the ground. Then what is the use of plucking so many fruits from the tree?"
Through this example we can understand the nature of leśyās. The emotions of the six persons are affected respectively with kṛṣṇa leśyā up to śukla leśyā.