The boulder opal is one of the rarest and most valuable forms of opal found in Australia and makes up less than 5 % of opal mined. It is very sparsely distributed through South West Queensland. It is predicted that boulder opal is going to run out in the next 10 years because of the difficulty clearing Native Title and EPA requirements of rehabilitation. It’s formed in the cracks and crevices of the ironstone boulders in gel form thousands of years ago and with the passing of centuries this jelly opal turned. Boulder opal occurs as a filling between the concentric layers or in random crevices in the ironstone. The boulder opal has a high loss factor when cutting, the yield is only 5% and has a rock waste factor of 95%. It is also the only opal suggestested to run out within the next 5 to 10 years and with the value (“it is suggested”) increasing by 15-25% each year. The boulder opal can certainly make a sound long term investment.