Red

• The phrase "red-hot" is a misnomer because red flames are the coolest.John Foxx/Stockbyte/Getty Images
  
  Both lithium and strontium produce a red flame when they burn. However, the strontium flame is brighter red. Red flames have the least amount of energy and have the lowest temperature.
  
  

Orange and Yellow

• Wood fires usually generate yellow, orange and red flames.Jupiterimages/Photos.com/Getty Images
  
  Calcium burns with an orange flame. Sodium burns bright yellow. A yellow tip is normal on a propane flame. A natural gas flame that has a lot of yellow indicates that there is not enough air in the mixture.
  
  

Green

• The color of a star gives us information about its chemical composition.Jupiterimages/Photos.com/Getty Images
  
  A number of elements generate flames in the green spectrum. Barium and molybdenum produce yellowish-green flames. Boron creates a bright green flame. Thallium burns pure green. Phosphorus and zinc burn bluish green.
  
  

Blue

• A butane lighter produces a blue flame.Ryan McVay/Photodisc/Getty Images
  
  Selenium, indium and arsenic burn blue. A normal natural gas --- methane --- flame also burns solid blue.