So it is winter and it is after 6pm, which means the light in here is low and I cannot make out individual minerals without getting up and going next door, so this quartz crystal chunk description isn't the most enticing.
 
This is a chunk of quartz found in the Southern Uplands, up in the hills of the hiking route. I brought it home thinking that it would be a quartz druzy or cluster, and instead when I cleaned it up, I realised it was not.
 
These are pieces of quartz which we like to call "teeth". They form in cavities in the rock where sediment leaches in over time, causing a sparkly surface all around the inside of the cavity which, when time and pressure close them together, look like teeth.
 
This one has a wide mouth.
 
I can see sparkling dark bits in there but I do not know what minerals they are. I can see definite quartz, potential calcite, maybe dolomite, and definitely at least one other mineral. It's a nice mix. It feels weighty in the hand indicating possible barite. This is the kind of rock you keep by your front door just in case you need to scare off a burglar. 
 
Please don't throw the rocks.