Spiderweb Turquoise is a term used to describe turquoise that looks like a spiderweb. It is not associated with any one mine, but many mines, some of the most notable being Kingman, Number 8, Lander Blue, Lone Mountain, Candelaria and others.
As described below from the book “Turquoise The Gem of the Centuries” by Oscar R. Branson, spiderweb turquoise can be thought of as small pieces of turquoise cemented together with the mother rock (matrix). It is when these pieces are polished or cross cut that the spider web design emerges.
When other materials appear within turquoise, those materials which often look like veins, are referred to as matrix or part of the “mother rock”. Matrix can range in color from honey gold (rhyolite, a volcanic rock) or brown (iron oxide) to jet black (iron pyrite aka iron sulfide) and many other color variations.
The matrix can be in large random blotches or it can appear as uniform lines around evenly spaced cubicles, almost pattern-like, which brings to mind a net or a spiderweb, thus the name.
In some parts of the world, turquoise stones with matrix are considered imperfect and clear turquoise stones are most desired but in the US, spiderweb turquoise has much more appeal and value.