“platform.” See commentary on Ezekiel 1:22.
“over the heads of the cherubim was something like a sapphire stone.” This is similar to Ezekiel 1:26.
“in appearance resembling a throne.” In this verse the throne is empty. God had come down from the throne in Ezekiel 9:3, and stops above the cherubim, and thus remounts His chariot-throne, in Ezekiel 10:18. C. F. Keil (Keil and Delitzsch Commentary on the Old Testament) punctuates the last Hebrew phrase as “He [God] appeared above them,” as if God was seated on the throne, however the English translations almost universally describe the scene with the throne being empty, which according to the chronology in Ezekiel, is correct.