Petrographic Description: Chocolite

Published 2009-02-25 by Chris

After exploring a small number of towns and cities in the United Kingdom I’ve come across a rock that I believe is completely new to science. (sorry for the blurry photos in this post, my phone camera is crap at close-ups).

Figure 1. A photograph of several types of the chocolite pseudomorph.

Figure 2. A detailed photograph of the chocolite pseudomorphs. a.) granite b.) obsidian c.) limestone d.) granite

Chocolite is a pseudomorph (Fig. 1), superficially appearing to be a range of rocks including obsidian, granite and limestone (Fig. 2). The pseudomorphic properties are, however, confined to a thin vineer (Fig. 3 a), revealing a reasonably consistent, non-indurated biologically-rich clay (Fig. 3 b) surrounding what looks like a calcite core (Fig. 3 c). Small inclusions made of peanite are present in the calcite core (Fig. 3 d).

Figure 3. A cross section showing the layered structure of a typical sample of chocolite. a.) the thing pseudomorphic vineer b.) a biologically-rich clay c.) the calcite core d.) a peanite inclusion.

The most surprising characteristic of chocolite is that it shares a property with halite and limestone in being 100% edible. This trait is more surprising given chocolite measures a perfect 10 on the deliciousness scale (Fig. 4). It’s smooth, creamy interior and sweet, crunchy outer shell make it a favourite for those who love rocks (Fig. 4 a).

Figure 4. Chocolite is delicious! a.) a geologist devouring a chocolite sample.

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