Like pet rocks or mood rings?
Sorry, ET, if you don't understand the symbolism, take it up with the Holy Spirit who inspired St. Peter to write:
As you come to Him, the living stone, rejected by men, but chosen and precious in God’s sight, you also, like living stones, are being built into a spiritual house to be a holy priesthood, offering spiritual sacrifices acceptable to God through Jesus Christ. For it stands in Scripture: “See, I lay in Zion a stone, a chosen and precious cornerstone; and the one who believes in Him will never be put to shame.” (I Peter 2:4-6)