So let man see from what he is created
Question

Did Allah create man from clay or from something else that is not fully described in the Quran?
Praise be to Allah.Firstly: 
Allah created Adam (peace be upon him) from the earth i.e., from what it contains. Allah says (interpretation of the meaning): 
“Thereof (the earth) We created you, and into it We shall return you, and from it We shall bring you out once again”
[Ta-Ha 20:55]
He created him from the dust of the earth, as He says (interpretation of the meaning): 
“Verily, the likeness of ‘Eesa (Jesus) before Allah is the likeness of Adam. He created him from dust…”
[Aal ‘Imraan 3:59]
There are many similar verses in the Quran. 
Then the dust was combined with water to form clay, as the Lord of the Worlds says (interpretation of the meaning): 
“He it is Who has created you from clay, and then has decreed a (stated) term (for you to die). And there is with Him another determined term (for you to be resurrected)”
[al-An’aam 6:2]
There are also many similar verses. 
This clay was sticky – or it was said, viscous – as it says in the verse (interpretation of the meaning): 
“Verily, We created them of a sticky clay”
[al-Saaffaat 37:11]
Ibn Manzoor said: the words laazib (sticky) comes from the root lazuba which has the meaning of becoming sticky and solid.  
Lisaan al-‘Arab, 1/738 
Then this sticky clay became muntin (stinking). Allah says (interpretation of the meaning): 
“And indeed, We created man from dried (sounding) clay of altered mud [min hama’in masnoon]”
[al-Hijr 15:26]
Al-Raazi said:
Al-hama’ means black mud.
(Mukhtaar al-Sihaah, p. 64). 
It says in Lisaan al-‘Arab (1/61):
Al-hama’ means black, stinking mud. In the Quran it says “min hama’in masnoon.” 
And it says in Lisaan al-‘Arab (13/227): 
“Masnoon means muntin (stinking), as in the verse ‘min hamaa’in masnoon.’ Abu ‘Amr said: this means altered and stinking. Abu’l-Haytham said: sunna al-ma’, fa huwa masnoon, i.e., the water changed, so it was altered (masnoon).” 
When this mud was mixed with sand, it became salsaal (dried clay). 
Al-Raazi said: 
Salsaal is hot mud mixed with sand, so it starts to clank or clatter when it dries. If it is baked with fire it becomes fired clay or earthenware pottery. 
Mukhtaar al-Sihaah, 1/154. 
It says in Lisaan al-‘Arab (11/382): 
Al-Salsaal min al-teen (clay made from mud) is that which has not been made into pottery. Any mud or clay that dries is described as salla saleelan (rattling or clattering) … i.e., it makes a noise like new pottery. Thus salsaal is likened to pottery, as in the verse,  
“He created man (Adam) from sounding clay like the clay of pottery”
[al-Rahmaan 55:14 – interpretation of the meaning]
All of this is confirmed by the hadeeth of Abu Moosa al-Ash’ari who said: “I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: ‘Allah created Adam from a handful that He gathered from the entire earth, so the sons of Adam come like the earth. Some of them are red, some are white, some are black and some are in between. Some of them are easy, some of them are difficult, some are evil and some are good.”
(Narrated by al-Tirmidhi, 2955; Abu Dawood, 4693. Al-Tirmidhi said that this hadeeth is hasan saheeh, and it was classed as saheeh by Ibn Hibbaan, 14/29; al-Haakim, 2/288; and al-Albaani in Saheeh Abi Dawood, 3926). 
This is how Adam was created: from the earth – i.e. from its dust – which was then mixed with water to form mud, which then became black, stinking mud. And this dust was created from the earth which is partly sand and when it is mixed it becomes sounding clay like the clay of pottery. 
Hence when Allah describes the creation of Adam in the Quran, in each case He describes one of the stages through which his creation passed and through which the mud was formed. So there is no contradiction in the verses of the Quran. 
Then after that the sons of Adam started to multiply and they were created through water which is the sperm and fluids which are emitted by men and women, as is well known. 
This is explained by the Quran in the verses (interpretation of the meanings): 
“And it is He Who has created man from water, and has appointed for him kindred by blood, and kindred by marriage”
[al-Furqaan 25:54]
“Then He made his offspring from semen of despised water (male and female sexual discharge)”
[al-Sajdah 32:8]
Ibn al-Qayyim (may Allah have mercy on him) said: 
When the perfection, complete power, all-encompassing knowledge, ever-executed will and utmost wisdom of the Lord decreed that His creation should be of materials of different kinds, and that they should vary in their forms and attributes and natures, His wisdom decreed that He should take a handful of dust from the earth, then mix it with water. So it became like black stinking mud. Then the wind was sent upon it and it dried out, until it became clay like pottery. Then it was given shape and limbs and faculties, and each part of it was given a shape suited to its purpose.
 Then he mentioned how people are created by means of intercourse and the emission of semen.
 Al-Tabaayun fi Aqsaam al-Quran, p. 204
 And Allah knows best.