I recently took some inspiration from the queen of glitter placement Polish All the Nails, and created a glitter placement mani using diamond shaped silver holographic glitters.
My base is the beautiful Cirque Magnum Opus, which is a purple-charcoal with a holo flame.
My spacing isn't perfect with these glitters, but I was happy with the overall effect. It's bloody hard to get those glitters evenly spaced, especially when the diamond shapes aren't all cut evenly.
Here are some bonus swatches of Magnum Opus on it's own. You can really see the two colours in the base of the polish. The first and third photos really show off the purple sheen, but the second photo shows the gold leaning charcoal. Its a very beautiful holo.