Question

Could you please explain a sign that appears in the Qur'an in surah Yusuf; I cannot find an explanation for it in the Qur'an when I look at the explanation for the different stops etc...It is a small diamond shape above the meem in the 6th or 7th word in this aayah from surah Yusuf.

The translation of the meaning being: ((They said: "O our father! Why do you not trust us with Yûsuf (Joseph), - when we are indeed to him sincere counselors?"))

May Allah reward you.

Answer

And May Allah reward you and all Muslims with goodness.  The little diamond is used to indicate that this word is read a special way.  In this aayah the word:  is read two ways, by  Hafs ‘an Aasim by the way of Shatabiyyah, both ways are acceptable ways of reading.  The with the shaddah on it is read either with (ishmaam), meaning the two lips are in a dhammah while saying the noon saakinah and holding it for the period of time that the longest form of ghunnah receives.  There is no sound accompanying this circling and protruding of the lips (the dhammah), it something only those looking at the reciter perceive. 

The other way of reading this is by making a quick dhammah equal to only ¾ of a normal vowel count on the first  of the two in the shaddah, and read the other as a normal fat-h.  

The reason for this is that the word is from with both of the  having vowels.  The two  have merged into one and therefore the resultant shaddah on the .  A merging of this type (both letters being voweled) is not at all common in the reading of Hafs.  The Prophet  recited this word three known different ways, but the chain of Hafs ‘an ‘Aasim by the way of Shatabiyyah has only two of these ways, as described above: either a dhammah of the two lips with no sound on the first of the shaddah and the second with a fat-h; or the first  is recited with a short dhammah ¾ the count of a regular vowel count and the second recited with a fat-h.   And Allah knows best.