Jealousy is a natural feeling among humans. Due to society and culture it gets controlled among humans. Some people control both by action and mind. Some control by action, but keep with in mind, some exhibit totally. Examples of jealousy an be traced even in our ancient Hindu scriptures.

(1) Story of Sage Vishwaamitra and Vashishth
Once when King Vishwaamitra was taking a round of his kingdom, he was hosted by Vashishth Jee. He felicitated him and his large army with the help of his Kaamdhenu cow. Seeing Vashishth's cow so powerful, Vishwaamitra Jee got jealous and asked that cow to give to him, but Vashishth Jee refused to part with her, as she was the only source for all Braahman's daily activities. When Vishwaamitra wanted to take her by force, Vashishth's only a small scepter stopped him to do so. He undrstood that it was his Yog's result, so he aspired for the position of Brahmarshi, and at last got succeeded in getting it. Even after that because of their personal jealousy, the poor King Harishchandra also became the victim. Read the full story here.

(2) Story of Dev Guru Brihaspathi and Asur Guru Shukra
Shukraachaarya had learnt Mrita-sanjeevanee Mantra after praying Shiv. On account of this Asur were getting reborn where as Devas were getting killed in Dev-Asur Sangraam. Brihaspati was not at all happy with Shukraa's this achievement. An Asur Guru knows something which a Deva Guru does not know? How is it possible? In the course of activities they forgot that they were Guru. This is clearly seen in the disguising story of Brihaspati as Shukraachaarya. Without taking the Mrit Sanjeevanee by efforts, Brihaspati hatched a crooked way to get the Mantra from Shukraachaarya. He sent his son Kach to learn under Shukraachaarya.

However Shukracharya even after understanding the purpose of his coming to him accommodated him and in peculiar circumstance had to teach that Mantra to Kach. He learnt the Mantra and went back to his father betraying Devayaanee, the daughter of Shukrachaarya. Read Brihaspati and Shukraachaarya; and Devayaanee and Kach.

If one reads Astrology treaties it could very well visualized, every where Shukra stands one foot up than Brihaspati and he was envious of the position of Shukra, but Shukra too takes pride in being one foot up above Brihaspati.

(3) Jealousy of Rukminee and Satyabhaama and that of Raadhaa
In the Krishn legends, Satyabhaamaa was always jealous of Rukminee, as she thought that Krishn loved Rukminee more than her. The weighing of Krishn with Gold is an illustrative side of it advocated by sage Naarad. Read this story here.

But both of them were jealous of Raadhaa, because both thought that Krishn loved Raadhaa more than them both and was always on His mind. Read the full story here - Raadhaa and Rukminee.

Jealousy in Modern Times
Modern times are also not free from jealousy, here are some examples --
--Jealousy in getting 1st and 2nd Position - The 2nd position man in any competition will appreciate the first position candidate openly, but in his inner mind he will be jealous of the first man. Although he might not express it in front of anybody but one could see it every minute on his face and in his indirect conversation. If cash is not involved, the jealousy might be a little less, if in cases of giving simply certificates jealousy is almost nil.
--In official carrier - Official careers are not without jealousy. If two people are at the same level and one gets promotion even beig less qualified, the junior one is jealous with him.
--New House Construction - The same feeling appear when another person construct a house with more architecture and beauty or even paint with good quality and appealing items, or even in tiling. People will say - His paint is not good. That house only looks beautiful, but it has lesser space than mine. Or his tiles has only color not the quality.
--Newspaper - Newspapers have lots of jealousy with each other about their circulation.
--Among children - We can see jealousy more with children. If one child wears a new dress, the other one will sprinkle ink on it to spoil it, or break their things, or steal it, or to make a new toy defective; etc
--Merchandise - In merchant establishment the jealousy is much more. You praise one hotel- The other hotel owner can never digest it. He will either immediately talk of the minuses there or try to make better than that. Purchase some thing from a shop and goes to another shop keeping the same - he will take it from you, show some defect and show another one from his shop saying that was without defect, but the interesting part of it is that his thing will have more defects than than the other one. The merchant enjoys his jealousy on your fooled face.

There is an old saying - There is no medicine for jealousy and baldness.