Sydney Grace Abigail (Deep) is a warm purple with a pearl finish that is permanent in palette and retails for $6.25. In comparison, Natasha Denona Rhodium (309DC) is a warm purple with a metallic finish that is permanent in palette and retails for $29.00.
Natasha Denona Rhodium (309DC) is 80% similar — it is more shimmery, lighter, warmer.