There are several references to God's Throne within the Bible:
In Matthew 5:34 Jesus tells us Heaven is God's throne
"But I say to you, Do not take an oath at all, either by heaven, for it is the throne of God"
This recalls God's opening statement in Isaiah 66:1
Thus says the Lord: “Heaven is my throne,and the earth is my footstool; what is the house that you would build for me, and what is the place of my rest?"
Other references to the Throne of God can be found in 2 Chronicles 18:18; Psalm 11:4; Hebrews 8:1; 12:2; Revelation 1:4; 3:21; 4:2; and many other verses in the Bible.
In Revelation Chapter 4 we get a description of the Throne from John:
...2 At once I was in the Spirit, and behold, a throne stood in heaven, with one seated on the throne. 3 And he who sat there had the appearance of jasper and carnelian, and around the throne was a rainbow that had the appearance of an emerald....5 From the throne came flashes of lightning, and rumblings[a] and peals of thunder, and before the throne were burning seven torches of fire, which are the seven spirits of God, 6 and before the throne there was as it were a sea of glass, like crystal.
And around the throne, on each side of the throne, are four living creatures, full of eyes in front and behind: 7 the first living creature like a lion, the second living creature like an ox, the third living creature with the face of a man, and the fourth living creature like an eagle in flight. 8 And the four living creatures, each of them with six wings, are full of eyes all around and within, and day and night they never cease to say, “Holy, holy, holy, is the Lord God Almighty, who was and is and is to come!”
9 And whenever the living creatures give glory and honor and thanks to him who is seated on the throne, who lives forever and ever, 10 the twenty-four elders fall down before him who is seated on the throne and worship him who lives forever and ever. They cast their crowns before the throne...
So we have a description of the surroundings, but what about the throne? We find that in Revelation Chapter 20:11:
Then I saw a Great White Throne, and Him who was sitting on it. The Earth and its skies (heavens) fled away from His presence, and there was no place found for them to hide.
Of course, this would depend on whether one takes the translation as literal or symbolic. Literally the Throne would be white, as described, with all the happening around it. Symbolically, the Throne is symbolic - and God's throne is just Heaven / nothing because He is a spirit.