Musnad Ahmad 30:2616

Waki' narrated to us, he said: Sa'dan al-Juhani narrated to us, from Abu Mujahid al-Ta'i, from Abu Mudillah, from Abu Hurairah, who said: We said: "O Messenger of Allah, tell us about Paradise, what is its construction?" He said: "A brick of gold and a brick of silver, its mortar is musk of intense fragrance, its pebbles are jacinth and pearls, and its soil is saffron and wars (a yellow dye). Whoever enters it shall abide eternally and not die, and shall be in bliss and not suffer. Their youth shall not fade, and their garments shall not wear out."