Although classified as grade C, these pink opal tumbled stones are really quite beautiful. The reason they're a lower grade is because of the mixture of colours and inclusions. Some of these are dendritic and although it may look like organic matter within the opal, these black patterns are actually crystal formations caused by manganese oxides.
Purer pink opals meaning stones that are not as heavily included and those with more uniform colour receive a higher grade. When it comes to tumbled stones we usually choose grade A and sometimes B but really loved these stones.
Although often referred to as a mineral, pink opal which is a variety of common opal is in fact a mineraloid. This word is used to describe a naturally occurring solid void of any significant crystal structure. Other examples of mineraloids include pearl, amber, shungite, moldavite and obsidian to name just a few. Minerals have a crystalline structure or in other words, are made up of crystals.
During the late 1970's with the rise of the New Age movement, the word 'crystals' started being used in relation to rocks and minerals. The term is neither used or recognised by mineral collectors, geologists or mineralogists. When used in relation to materials such as lapis lazuli and opal, it's scientifically incorrect.
Much of the opal that's mined around the world is common opal which unlike the precious variety, does not exhibit 'play of colour' or iridescence. Although the vast majority of pink opal comes from the western foothills of the Andes in Peru, it can also be found in Australia and Mexico.
Material with an exceptionally pink colour is often (but not always) enhanced because people have always been drawn to colourful stones.
Opals contain a significant amount of water usually between 6 and 10%. For this reason it's important not to allow them to dry out because a dehydrated stone will develop cracks. Wiping stones with a damp cloth every couple of months is enough to prevent dehydration. They could also be sealed in a plastic bag with some damp cotton wool. Opals should never be positioned in direct sunlight or anywhere too warm.
Our pink opal tumbled stones are a mixture of larger sizes. With some being slightly smaller than others we have split them into medium and large.