The stone in the necklace sure looks like Lander Blue. Check out similar stones at nevadagem.com. Unfortunately, without documentation of some sort, it could be another mine. You might get closer with research of the maker.
Check out my buckle in Blue Winds Lander Blue Little Bert King Belt Buckle & History. I’m confident the stones are Lander Blue especially with the original 1970s stickers and the research done by @Steve .