Generally Australian Opal that displays a crack is set at 10-20% of the value of a stable opal of similar qualities. Most Australian opal is very stable with black opal considered the most stable due to its smaller molecules. These can be air bubbles, vegetation matter and even potch. The image above is an Ethopian Opal with an inclusion. Crazed opals can be treated with Opticon which stabilises the Opal. They are not recommended for use in Jewelry. Crazed opal is mostly kept as specimens or collectors pieces. CRAZINGĬrazing looks like multiple crack lines. Many cracked opals are set as pendants for this reason and are able to be worn most of the time. Many cracked opals will hold but the biggest problem is if an opal is cracked and in a ring, the everyday wear and tear and knocks will break the Opal. External crack lines in a polished opal can be cut out but obviously this decreases the size and value of the Opal.Ĭracked opals do not necessarily mean that they will fall apart. Some Opal miners have stones with cracks inside them that have had no movement.

Internal cracks have been shown to be stable and not continue to grow. External cracks will decrease the value / price more than internal cracks. If you see a line inside the opal and it reflects light then it is a crack in the stone. CRACKSĪ crack can be a minor or major fault line. If your Opal does have fracture lines in it or it has crazed do not put it in an ultrasonic cleaner as it may destroy the Opal. While there is nothing wrong with buying an Opal that is crazed or cracked it is important that the buyer is made aware before the purchase. There is a major difference between the two and we will show you what it is. Many opal cutters will sell stones that have cracks or crazing in their opals.

What is crack cut with