This video explains the components of TotBlocks, a series of 3D-printed building blocks used to construct the crystal structures of minerals, how to build chains from them, and how these chains can be linked together. The main pieces of TotBlocks are the T (tetrahedral) and O (octahedral) modules and each of these modules can have a positive or negative orientation based on the direction the apices (up versus down). In some minerals, single octahedron pieces and vertical stacking pegs are also used in their structures. To construct a T-O-T module, an O module is stacked on a T⁺ module and a T⁻ module is stacked on the O module. This pattern can be repeated for different chain widths and for both O⁺ and O⁻ modules. These T-O-T modules can be connected widthwise into phyllosilicate-type, pyribole-type, or palysepiole type linkages. Equipped with these different sizes of chains and the different ways we can connect them, we can build a multitude of minerals that can come in many shapes and sizes.