10 D'Addario And Other Rosin Blocks Dark & Light Violin Cello Viola Music Supply. Some new or lightly used. 5 light natural rosin (VR200) and 5 dark natural rosin (VR300). One is crumbled and very well used. A couple have cracks through them as pictured but are perfectly usable. Brands are D'addario and Super sensitive musical string co.