Ezekiel 28:14 in the Masoretic text and the Allepo Codex are identical.
The Cambridge New English Bible (1970) translates the verse as "I set you with a towering cherub as guardian; you were on God's holy hill and you walked proudly among stones that flashed with fire" and in 16, "stones that flashed like fire".
A. S. Hartom's Hebrew commentary (published 1953) of Umberto Cassuto's Masoretic text translates the literal Hebrew "stones of fire" as "sparkling stones" (in modern Hebrew), that is, cut gemstones, a continuation of the imagery from the previous verse.
The unattributed translation of 28:14 in the OP is overall much closer to the original Hebrew text than the translation in the Cambridge New English Bible, however it's "stones of fire" is probably too literal a translation and gives the impression of a proper name that would have been known to the contemporary reader, which I believe it is not. This might be a simple literal translation in a case where the translator was at a loss.
The imagery of the anointed cherub would be familiar to the contemporary reader as the gold plated cherubs in the holy of holies of the Temple in Jerusalem whose wings over arched the ark of the covenant. "Over arched" might be a better translation than the "guardian" of the OP translation. The "holy mountain of God" is also a contemporary term for the hill above the city of David where the Temple once was. The only Temple imagery that includes sparkling stones is the image of the Urim and Tumim breastplate worn by the high priest that includes many of the stones mentioned in verse 13. The Urim and Tumim had twelve stones representing the twelve tribes and was used to make inquiries of the divine will. The stones were said to flash with a fiery light in accordance with the answer to a question. This image is supported by the first word of verse 15, "tamim" (innocent or without blemish), an oronym of "thumim" based on the same root, which though not used in 14, might be being suggested by the imagery.
Yehoshua Brand in Ceramics in Talmudic Literature claims that the "stones of fire" in Ezekiel 28 is one of the OT names for glass and alludes to the immensely lucrative Phoenician glass industry in Tyre. The imagery in 14 is a continuation of the imagery of precious stones from 13. Other names for glass or the glass industry identified by Brand are:
- Deuteronomy 33:16 "the hidden wealth of the sand"
- Ezekiel 40:16 "windows"
- Joshua 11:8 "Misrephoth"
- Isaiah 64:1 "water"
- Isaiah 54:12 "gates of garnet [or firestone]"
- Proverbs 20:15 Hebrew word following "coral" or "pearls" not in English trnalstions
- Psalms 37:20
- Zakaraiah 14:6
- Jeremiah 25:34
- Lamentations 4:1
- Exodus 1:14 "hard work"
- Psalms 81:7
[Translation of references not completed - ER]
The Temple imagery in 28:14 could be allusion to parallel images in Tyre; the anointed alluding to the olive oil industry of the area, the unassailable island position of Tyre being like the guardian chrubim, the shrine of Al Mina being likened to the mountain of God, and the glassworks parallel to the Urim and Thumim.
If this interpretation is correct, then the prophecy in 28:12-19 is an example of the principle of "measure for measure" (mida k'neged mida). As the rulers of Tyre gloated in the downfall of the beautiful sanctuary in Jerusalem (26:2), so their beautiful commercial sanctuary on Tyre will be destroyed.