Nuclear bodies frequently found near or associated with Cajal bodies (also called coiled bodies or CBs). Gemini of coiled bodies, or 'gems', are similar in size and shape to CBs, and often indistinguishable under the microscope. Unlike CBs, gems do not contain small nuclear ribonucleoproteins (snRNPs); they contain a protein called survivor of motor neurons (SMN) whose function relates to snRNP biogenesis. Gems are believed to assist CBs in snRNP biogenesis, and to play a role in the etiology of spinal muscular atrophy (SMA).