Requirements of Proper Hijab
Question

I wanted to know about a matter concerning the right hijab. What is the proper hijab? I mean so many different hijabs are to choose from. I have a friend from Denmark and she converted to Islam for a while now, and she's pleased ( Alhamdulilllah) and she wants to wear the right Hijab.
Could you please tell us where it says that the hijab should be long (jilbab) over the chest? She really needs this! Thank you
Praise be to Allah.Shaykh al-Albani (may Allah have mercy on him) said:
Conditions of proper hijab

 It should cover all the body apart from whatever has been exempted.

Allah says (interpretation of the meaning):
“O Prophet! Tell your wives and your daughters and the women of the believers to draw their cloaks (veils) all over their bodies (i.e. screen themselves completely except the eyes or one eye to see the way). That will be better, that they should be known (as free respectable women) so as not to be annoyed. And Allah is Ever Oft-Forgiving, Most Merciful.” 
This verse clearly states that it is obligatory to cover all of a woman’s beauty and adornments and not to display any part of that before non-mahram men (strangers) except for whatever appears unintentionally, in which case there will be no sin on them if they hasten to cover it up.
Al-Hafiz ibn Kathir said in his Tafseer:
“This means that they should not display any part of their adornment to non-mahrams , apart from that which it is impossible to conceal. Ibn Mas’ud said: such as the cloak and robe, i.e., what the women of the Arabs used to wear, an outer garment which covered whatever the woman was wearing, except for whatever appeared from beneath the outer garment. There is no sin on a woman with regard to this because it is impossible to conceal it.”

It should not be an adornment in and of itself.

Allah says (interpretation of the meaning):
“And not to show off their adornment.” [al-Nur 24:31] The general meaning of this phrase includes the outer garment, because if it is decorated it will attract men’s attention to her. This is supported by the verse in Surat al-Ahzab (interpretation of the meaning):
“And stay in your houses, and do not display yourselves like that of the times of ignorance.” [al-Ahzab 33:33]. 
It is also supported by the hadith in which the Prophet (peace and blessings of Allah be upon him) said: There are three, do not ask me about them: a man who leaves the jama’ah (larger Muslim community), disobeys his leader and dies disobedient; a female or male slave who runs away then dies; and a woman whose husband is absent and left her with everything she needs, and after he left she made a wanton display of herself. Do not ask about them.” (Narrated by al-Hakim, 1/119; Ahmad, 6/19; from the hadith of Faddalah bint ‘Ubayd. Its isnad is sahih and it is in al-Adab al-Mufrad).

It should be thick and not transparent or see-through because it cannot cover properly otherwise. Transparent or see-through clothing makes a woman more tempting and beautiful. Concerning this the Prophet (peace and blessings of Allah be upon him) said: “During the last days of my ummah, there will be women who are clothed but naked, with something on their heads like the humps of camels. Curse them, for they are cursed. Another hadith adds: They will not enter Paradise or even smell its fragrance, although its fragrance can be detected from such and such a distance.” (Narrated by Muslim from the report of Abu Hurayrah)

Ibn ‘Abd al-Barr said: “What the Prophet (peace and blessings of Allah be upon him) meant was women who wear clothes made of light fabric which describes and does not cover. They are clothed in name but naked in reality.” (Transmitted by al-Suyuti in Tanwir al-Hawalik, 3/103)

 It should be loose, not tight so that it describes any part of the body.

The purpose of clothing is to prevent fitnah (temptation), and this can only be achieved if clothes are wide and loose. Tight clothes, even if they conceal the colour of the skin, still describe the size and shape of the body or part of it, and create a vivid image in the minds of men. 
The corruption or invitation to corruption that is inherent in that is quite obvious. So the clothes must be wide. Usamah ibn Zayd said: The Messenger of Allah (peace and blessings of Allah be upon him) gave me a thick Egyptian garment that was one of the gifts given to him by Dihyah al-Kalbi, and I gave it to my wife to wear. He said, Why do I not see you wearing that Egyptian garment? I said, I gave it to my wife to wear. He said, Tell her to wear a gown underneath it, for I am afraid that it may describe the size of her bones.” (Narrated by al-Diya al-Maqdisi in al-Ahadith al-Mukhtarah, 1/442, and by Ahmad and al-Bayhaqi, with a hasan isnad)

It should not be perfumed with bakhur or fragrance .

There are many hadiths which forbid women to wear perfume when they go out of their houses. We will quote here some of those which have good chains of narration:

Abu Musa al-Ash’ari said: The Messenger of Allah (peace and blessings of Allah be upon him) said: Any woman who puts on perfume then passes by people so that they can smell her fragrance, is an adulteress.
Zaynab al-Thaqafiyyah reported that the Prophet (peace and blessings of Allah be upon him) said: If any one of you (women) goes out to the mosque, let her not touch any perfume.
Abu Hurayrah said: The Messenger of Allah (peace and blessings of Allah be upon him) said: Any woman who has scented herself with bakhur (incense), let her not attend ‘Isha prayers with us.
Musa ibn Yasar said that a woman passed by Abu Hurayrah and her scent was overpowering. He said, O female slave of al-Jabbar, are you going to the mosque? She said, Yes, He said, And have you put on perfume because of that? She said, Yes. He said, Go back and wash yourself, for I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: If a woman comes out to the mosque and her fragrance is overpowering, Allah will not accept any prayer from her until she goes home and washes herself.

These hadiths are general in implication. Just as the prohibition covers perfume applied to the body, it also covers perfume applied to the clothes, especially in the third hadith, where bakhur (incense) is mentioned, because incense is used specifically to perfume the clothes.
The reason for this prohibition is quite clear, which is that women’s fragrance may cause undue provocation of desires. The scholars also included other things under this heading of things to be avoided by women who want to go to the mosque, such as beautiful clothes, jewellery that can be seen, excessive adornments and mingling with men. (Fath al-Bari, 2/279)
Ibn Daqiq al-’Id said:
“This indicates that it is forbidden for a woman who wants to go to the mosque to wear perfume, because this causes provocation of men’s desires. This was reported by al-Manawi in Fayd al-Qadir, in the commentary on the first hadith of Abu Hurayrah quoted above.”

 It should not resemble the clothing of men .

It was reported in the authentic hadiths that a woman who imitates men in dress or in other ways is cursed. There follow some of the hadiths that we know:

Abu Hurayrah said: The Messenger of Allah (peace and blessings of Allah be upon him) cursed the man who wears women’s clothes, and the woman who wears men’s clothes.
‘Abd-Allah ibn ‘Amr said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: They are not part of us, the women who imitate men and the men who imitate women.
Ibn ‘Abbas said: The Prophet (peace and blessings of Allah be upon him) cursed effeminate men and masculine women. He said, Throw them out of your houses. He said: The Prophet (peace and blessings of Allah be upon him) expelled So and So, and ‘Umar expelled So and So. According to another version: The Messenger of Allah (peace and blessings of Allah be upon him) cursed men who imitate women and women who imitate men.
‘Abd-Allah ibn ‘Amr said: The Messenger of Allah (peace and blessings of Allah be upon him) said: There are three who will not enter Paradise and Allah will not even look at them on the Day of Resurrection: one who disobeys his parents, a woman who imitates men, and the dayyuth (cuckold, weak man who feels no jealousy over his womenfolk).
Ibn Abi Malikah whose name was ‘Abd-Allah ibn ‘Ubayd-Allah said: It was said to ‘Aishah (may Allah be pleased with her), What if a woman wears (men’s) sandals? She said: The Messenger of Allah (peace and blessings of Allah be upon him) cursed women who act like men.

These hadiths clearly indicate that it is forbidden for women to imitate men and vice versa. This usually includes dress and other matters, apart from the first hadith quoted above, which refers to dress only.
Abu Dawud said, in Masail al-Imam Ahmad (p. 261): I heard Ahmad being asked about a man who dresses his slave woman in a tunic. He said, “Do not clothe her in men’s garments, do not make her look like a man.” Abu Dawud said: I said to Ahmad, ‘Can he give her bachelor sandals to wear?’ He said, ‘No, unless she wears them to do wudu. I said, ‘What about for beauty?’ He said, ‘No.’ I said, ‘Can he cut her hair short?’ He said, ‘No.’

 It should not resemble the dress of disbelieving women .

It is stated in Shari`ah that Muslims, men and women alike, should not resemble or imitate the disbelievers with regard to worship, festivals or clothing that is specific to them. This is an important Islamic principle which nowadays, unfortunately, is neglected by many Muslims, even those who care about religion and calling others to Islam. This is due either to ignorance of their religion, or because they are following their own whims and desires, or because of deviation, combined with modern customs and imitation of non-Muslims in Europe. This was one of the causes of the Muslims decline and weakness, which enabled the foreigners to overwhelm and colonize them. “Verily, Allah will not change the condition of a people as long as they do not change their state themselves.” [al-Ra’ad 13:11 interpretation of the meaning]. If only they knew.
It should be known that there is a great deal of sound evidence for these important rules in the Quran and Sunnah, and that the evidence in the Quran is elaborated upon in the Sunnah, as is always the case.

 It should not be a garment of fame and vanity.

Ibn ‘Umar (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings of Allah be upon him) said: “Whoever wears a garment of fame and vanity in this world, Allah will clothe him in a garment of humiliation on the Day of Resurrection, then He will cause Fire to flame up around him.” (Hijab al-Marah al-Muslimah, p. 54-67)
And Allah knows best.