In back to back chapters, Revelations talks about those who masquerade as Jews. Look it up to confirm if you want to.
Revelations 2:9 and Revelations 3:9
Revelations 2:9
I know thy works, and tribulation, and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan.
Revelation 3:9
Behold, I will make those of the synagogue of Satan who say that they are Jews and are not, but lie—behold, I will make them come and bow down before your feet, and they will learn that I have loved you.
How about Revelations 4:3
3 And he that sat was to look upon like a jasper and a sardine stone: and there was a rainbow round about the throne, in sight like unto an emerald.
Here is a jasper stone:
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