Muslim men, according to the prophetic hadith, are prohibited to wear gold. The same they are not allowed to use gold utensils. If it is something light such as the nib of a pen then it is OK.
Theeminent Muslim scholar Sheikh `Abdel-KhaliqHasan Ash-Shareef, a renowned scholar and Da`iyah, states: “There is no problem in using such a pen as it is only a little part of it which is made of gold. If the whole pen is made of gold, then it will not be allowed to use.