The majority of Christians think of the Ten Commandments as being inscribed on tablets of grey stone. However, rabbinical Judaism as found in the Talmud and Mishnah teaches that the tablets of the law were made of sapphire. This was done to point to God’s creation in the heavens and to His throne. The Talmud and Mishnah are far from being authoritative and even blasphemous in several respects, especially when teaching on Yeshua (Jesus). Nevertheless, that does not mean that everything taught in rabbinical Jewish tradition is inaccurate. Ancient tradition is especially useful in understanding what the Jewish people held to on scores of topics. Scripture itself corroborates much of what the tradition has to say regarding the sapphire Ten Commandments.
and they saw the God of Israel. There was under his feet as it were a pavement of sapphire stone, like the very heaven for clearness. Exodus 24:10 (ESV)
Moses and the rest of Israel’s leadership were given the profound privilege of seeing God. God appeared in the person of the Son as He expresses God’s image to man (cf. John 1:18; 14:9). Under God’s feet was something that appeared to be sapphire. The Hebrew cappiyr (pronounced sap-peer’) can either be translated as a sapphire or lapis lazuli. It is from this pavement that God carved out the tablets upon which He wrote the law as recorded in Exodus 24:12:
The LORD said to Moses, “Come up to me on the mountain and wait there, that I may give you the tablets of stone, with the law and the commandment, which I have written for their instruction.”
The stone from which the tablets were fashioned almost certainly refers to that which appeared to be sapphire only two verses earlier. The sapphire is the only type of stone mentioned in the context. It would be a leap to conclude that the tablets were made from any type of stone other than that which was recorded. Unfortunately, many do not even consider the sapphire tablets an option because they have been unconsciously influenced by western images of the Ten Commandments. No doubt that the Charleton Heston film alone has cemented certain imagery into the culture (a fine movie in any respect).
It is even a distinct possibility that the tablets were carved from God’s throne. Consider Ezekiel 1:26:
Above the expanse over their heads was something like a throne, resembling a sapphire stone. Above the shape of the throne was a figure of human appearance.
The figure upon this throne was the likeness of the glory of YHWH (Ezek. 1:28). Like the appearance of God to the elders of Israel, this too was God in the person of the Son. These two accounts of God appearing are of such a similarity that it is reasonable to conclude that the sapphire foundation and the sapphire throne are one in the same. Not only were the tablets written on by God, but they were themselves a work of God (Ex. 32:16). They were then of supernatural origin. The tablets coming from God’s throne is consistent with both the narrative and the foundational importance of God’s law.
Even today it is evident that the color blue is important to both observant Jews and secular Israel. The color was intended to remind the Israelites to observe God’s law. Numbers 15:37-39:
The LORD said to Moses, “Speak to the people of Israel, and tell them to make tassels on the corners of their garments throughout their generations, and to put a cord of blue on the tassel of each corner. And it shall be a tassel for you to look at and remember all the commandments of the LORD, to do them, not to follow after your own heart and your own eyes, which you are inclined to whore after.
With the idea of tablets of sapphire in mind, it becomes obvious why a cord of blue would make the wearer mindful of the law. It makes all the more sense that Isaiah would foresee Israel being blessed with a foundation of sapphires (Is. 54:11).
Why does the Torah enjoin us regarding techelet? Because techelet resembles sapphire, and the Tablets were made of sapphire, to tell you that as long as Bnei Yisrael gaze upon this techelet they are reminded of what is inscribed on the Tablets and observe the commandments, therefore it is written, ‘And you shall see it [the techelet string] and remember all of the commandments of G-d and you shall do them.’
– Mishnat Rabbi Eliezer, Chap. 14
 Obadiah Bertinoro on Mishnah, Avot 5:6. Cf. Babylonian Talmud, Nedarim 38a. Note the value of the pieces of the broken tablets.