A tesseract is a four-dimensional hypercube — a cube's analog in four dimensions. A cube has six square faces, and a tesseract has eight cubical cells which form its hypersurface. The term originates from the Greek τέσσερεις ακτίνες ("four rays"), for the number of lines emanating from one vertex.
In Madeleine L'Engle's
A Wrinkle in Time, the protagonist Meg "wrinkles time" through a tesseract, which acts as a portal or worm-hole leading to another part of space-time.
This pendant is 1.3 in (3.3 cm) from top to bottom, including the loop. A 2 mm chain is recommended. For example, this
Sterling Silver 2mm diamond cut rope chain necklace in 18k gold plating goes very nicely with the gold materials.