Help identify initials D and t over k and the stone inside

[jcm]

I believed this to be Native american but not 100% sure. I am having a little trouble ID'ing this makers mark though. And the stone that is in it.
Any help greatly appreciated
Thanks again


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[ValkyrieVixen]

It's DTR, made by the Desert Rose Trading company, a southwest jewelry company owned, I believe, by Jay King who sells his items on HSN. The stone looks like lab created/Gilson Opal. Even though not NA his items sell well.
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