.GCSX File Extension
File TypeMicrosoft Office SmartArt Color File
What is a GCSX file?
File used by the SmartArt component of Microsoft Office; saves a custom color that can be added to the SmartArt Colors gallery; can be created by the user or may be one of the preinstalled Office colors; used for stylizing SmartArt graphic layouts, which are stored in .GLOX files.
GCSX files used Open XML formatting, which is the format used for Microsoft Word (.DOCX), Microsoft PowerPoint (.PPTX), and Microsoft Excel (.XLSX) files. You can create custom color styles by constructing a GCSX file using this format.
NOTE: SmartArt is available with Microsoft Office 2007 and later.