In which everyday products quartz (silicon dioxide) might be found?

Hello, I found a quartz stone can you help?uk?

• hello, I found a quartz stone , but this stone is difrent of other quartz stones in color, usually quartz is white stone, but this rock of quartz is a very dark yellow almost brown, I cut the stone in half and not found signs of gold, I used a magnifying glass and also do not see anything gold: will be possible that this quartz stone has some gold on it? I want to hear the opinion especially geologists and gold prospectors . thanks evryone

• Answer:

  Quartz comes in quite a variety of types and colours. The article below will give you a more detailed view. http://en.wikipedia.org/wiki/Quartz#Coarsely_crystalline_varieties The occurrence of gold in quartz is certainly well known, but rare and not evenly distributed around the world. The overall concentration being being 0.005 parts per million. There is relatively little gold in the UK. When you said "signs of gold" I'm not clear what you mean. Iron sulphide crystals (pyrites), which are yellowish in colour can be mistaken for gold