Urban Decay Solstice is a warm copper with a sparkle finish that is discontinued and retails for $20.00. In comparison, Natasha Denona Calypso Blue (05M) is a warm duochrome with a sparkle finish that is permanent in palette and retails for $29.00.
Natasha Denona Calypso Blue (05M) is 90% similar — it is less shimmery.