i believe the word clay is used to refer to the description of
modelling from earth,
since it does in other verses use words like tin, sualsual, ard, and turab,
these have diverse meanings - yet are used to describe the creation of man.
The similitude of Jesus before God is that of Adam; he created him from dust (turab) , then said to him: 'be': and he was.
Quran 3:59
yet we know that Jesus (pbuh) was born of woman.
clay argil dust mud earth etc. - so it doesn't necessarily mean a certain type of clay - but mud or soil,
i've lived in Bangladesh and i've seen them make baked mud bricks out of pond and river soil.
if you consider carefully - you will find that every component used to compose man comes from the ground - including water plants, cattle, milk, fruit and flying fowl.
this is not a contradiction.
there was also a site i came across recently which stated that there was a contradiction in the Quran since it said that :
Verily We created man of potter's clay of black mud altered,
And the jinn did We create aforetime of essential fire.
S. 15:26-27 Pickthall; cf. 55:15; 7:12; 38:76
and then:
Have not those who disbelieve known that the heavens and the earth were of one piece, then We parted them,
and we made EVERY living thing of water? Will they not then believe?
S. 21:30 Pickthall
they believed this to be a contradiction since fire and water are not the same thing, and many people have tried to explain it away by saying that spirits and satan etc were other other worldly so it doesn't count as from earth etc,
however, due to recent scientific findings - we have found that clean smokeless fire is from water.
even the magnetic ELF frequency of the electricity running through our brain matches that of the Earth's electromagnetic field.
it's called schumann resonance.
so we can say that the debunkers and explainers may be limited in knowledge - but Almighty God's wisdom is Infinite.
And God knows best.