Slices of rocky road, made with different coloured ingredients so as to look like the minerals in a rock.
  • Art and Design
  • Geology
  • Key Stage 1
  • Key Stage 2
  • Science

The Scientific Kitchen

Learn about Markfieldite – one of Charnwood Forest’s most exciting rocks – in a fun and accessible way. Markfieldite, largely used in the modern period for road-building material, is the region’s very own original Rocky Road! This lesson plan provides step-by-step guidance on making your own edible geology.

Around 560 million years ago, during the Ediacaran period when our oldest fossils appeared, a number of igneous intrusions occurred in Charnwood Forest. An igneous intrusion is when molten rock called magma rises through the Earth’s crust, but cools and solidifies underground before it reaches the surface. This is how the South Charnwood Diorites formed, a rock type better known as Markfieldite. Markfieldite is one of Charnwood Forest’s most notable rock types, containing a mix of pink, green and black minerals. Historically, it was used to make kerbstones and paving setts, and continues to be quarried at Cliffe Hill, mainly for road building material. Now you can make your own tasty Markfieldite, using the recipe below.


600g white chocolate

2 tbsp clear honey

70g mini pink marshmallows

70g raisins

6 digestive biscuits

92g pack of mint Aero bubbles

50g pistachio nuts (optional—check for nut allergies)


  1. Crush the biscuits by putting them into a bag and breaking them up using a rolling pin.
  2. Roughly chop up the mint Aero bubbles into quarters.
  3. If using, roughly chop up the pistachios.
  4. Break up the white chocolate into a bowl, and add the honey.
  5. Melt the white chocolate and honey together. You can use a microwave, stirring now and again; or you can set the bowl over a pan of just-simmering water (you’ll only need about 3cm of water in the pan). If you choose this method, melt the chocolate slowly, being careful not to overheat it.
  6. Once melted, take the chocolate and honey mixture off the heat. Let it cool for a couple of minutes before adding in the crushed biscuits, raisins, and nuts (if using). Stir together.
  7. Now add in the marshmallows and mint Aero and stir again.
  8. Line a Brownie pan with some clingfilm, pour the mixture into the pan. Spread and level it with a spoon. Now put the pan into a fridge for at least an hour. Cut and enjoy! Oh, and do send us pictures!
A polished piece of Markfieldite, approximately 5 cm across, showing pink, green, and black minerals. From OUMNH.

A polished piece of Markfieldite, approximately 5 cm across, showing pink, green, and black minerals. From OUMNH.