Lesya

Lesya, according to the Jain theory of karma, is the coloring of the soul on account of its association with the karmic matter. The colour of "leśyā" varies from person to person depending on the psychic states and mental activities behind an action. The coloring of the soul is explained through the analogy of crystal, that acquires the color of the matter associated with it. In the same way, the soul reflects the qualities of colour, taste, smell and touch of associated karmic matter, although it is usually the colour that is referred to when discussing the "leśyās." Paul Dundas notes the key text expressing this Jain doctrine, explaining how the literary form of the text is helpful in dating and reconstructing the history of transmission.
A full statement of the theory of "lesya" occurs in chapter 34 of the Uttaradhyayana, one of the fundamental "sutras" of the scriptural canon. Inspection of the metrical structure there, which consists of a cluster of old "sloka" verses amplified by twice as many verses in the "arya metre", makes clear that a great deal of ancient editorial care was taken to ensure that an original rudimentary description of this dimension of karma became fully cogent.
Colours.
The ancient Jain text "Uttarādhyayana-sūtra" speaks of six main categories of "leśyā" represented by six colours – black (krishna), blue (neel), grey (kapot), red (tejo), yellow (padma) and white (shukla). "Uttarādhyayana-sūtra" describes the mental disposition of persons having black and white "leśyās":
A man who acts on the impulse of the five sins, does not possess the three "guptis", has not ceased to injure the six (kinds of living beings), commits cruel acts, is wicked and violent, is afraid of no consequences, is mischievous and does not subdue his senses – a man of such habits develops the black "leśyā".
— "Uttarādhyayana-sūtra", 34.21:22
A man of the following qualities: envy, anger, want of self-control, ignorance, deceit, want of modesty, greed, hatred, wickedness, carelessness, love of enjoyment; a man who pursues pleasures and does not abstain from sinful undertakings, who is wicked and violent – a man of such habits develops the blue "leśyā".
— "Uttarādhyayana-sūtra", 34.23:24
A man who is dishonest in words and acts, who is base, not upright, a dissembler and deceiver 3, a heretic, a vile man, a talker of hurtful and sinful things, a thief, and full of jealousy – a man of such habits develops the grey "leśyā".
— "Uttarādhyayana-sūtra", 34.25:26
A man who is humble, steadfast, free from deceit and inquisitiveness, well disciplined, restrained, attentive to his study and duties, who loves the Law and keeps it, who is afraid of forbidden things and strives after the highest good–a man of such habits develops the red "leśyā".
— "Uttarādhyayana-sūtra", 34.27:28
A man who has but little anger, pride, deceit, and greed, whose mind is at ease, who controls himself, who is attentive to his study and duties, who speaks but little, is calm, and subdues his senses–a man of such habits develops the yellow "leśyā".
— "Uttarādhyayana-sūtra", 34.29:30
A man who abstains from constant thinking about his misery and about sinful deeds, but engages in meditation on the law and truth only, whose mind is at ease, who controls himself, who practises the "samitis" and "guptis", whether he be still subject to passion or free from passion, is calm, and subdues his senses–a man of such habits develops the white "leśyā".
— "Uttarādhyayana-sūtra", 34.31:32 
Consequences.
The black, blue and grey are inauspicious "leśyā" due to which the soul takes birth in various-unhappy states of existence. The yellow, red and white are the auspicious "leśyās" that enable a soul to take birth in various happy states of existence. According to Jain texts, a person with black Leshya will go to hell. a person with blue lesya is reincarnated in plant life and person with grey lesya is reincarnated in animal life. On the other hand, persons having red lesya are reincarnated as humans, those with yellow lesya are reincarnated as celestial beings while those having white lesya are either reborn in highest heaven or having achieved purity attain liberation.
Parable of tree.
The Jain texts further describe the mental dispositions of a soul on account of "leśyās" with an example of the reactions of six persons who are travelers, on seeing a fruit-bearing tree. They see a tree laden with fruits and begin to think of getting those fruits: one of them suggests uprooting the entire tree and eating the fruits; the second one suggests cutting the trunk of the tree; the third one suggests cutting the branches only; the fourth one suggests cutting the twigs; the fifth one suggests plucking the fruits only; the sixth one suggests picking up only the fruits that have fallen down. The thoughts, words and bodily activities of each of these six travellers are different based on their mental dispositions and are respectively illustrative of the six "leśyās". The person with the black "leśyā", having evil disposition, thinks of uprooting the whole tree even though he wants to eat only one fruit. The person proposing to cut the tree trunk has blue "leśyā", the one suggesting cutting branches has grey "leśyā", the person suggesting cutting twigs has red lesya and the person thinking of simply plucking the fruits has yellow "leśyā". On the other hand, the person with the white "leśyā", having pure disposition, thinks only of picking up fruits fallen on the ground sparing the tree.