Sahih Bukhari Volume 6, Book 65, Hadith 4882

‏ وَجَنَّتَانِ مِنْ فِضَّةٍ، آنِيَتُهُمَا وَمَا فِيهِمَا، وَجَنَّتَانِ مِنْ كَذَا آنِيَتُهُمَا، وَمَا فِيهِمَا، وَمَا بَيْنَ الْقَوْمِ وَبَيْنَ أَنْ يَنْظُرُوا إِلَى رَبِّهِمْ إِلاَّ رِدَاءُ الْكِبْرِ عَلَى وَجْهِهِ فِي جَنَّةِ عَدْنٍ ‏"

And there are two gardens, the utensils and contents of which are made of silver; and two other gardens, the utensils and contents of which are made of so-and-so (i.e. gold) and nothing will prevent the people staying in the Garden of Eden from seeing their Lord except the curtain of Majesty over His Face."