I recently moved to okc from Texas. I know there's some interoperability, and that Toll Tags are accepted. However, I have a TxTag, similar to a toll tag, but put out by TxDot.
Topaz is commonly used for Friendship Rings and it is nicknamed 'the gem of friendship'. Topaz is considered in some cultures to be the ultimate representation of friendship and fidelity.
Friendship rings can serve other purposes in addition to symbolizing a bond between friends. These rings are sometimes thought to be engagement rings or wedding bands, particularly when worn by a male and female duo.