All Types of Opal
Collectors of opal are ever enthralled with how many variations of the gem species exist. While some gemstones “are what they are,” opal has many incarnations owing to the fascinating way in which these gemstones are formed.
The name opal derives from the Sanskrit word upala for stone. But this species is then subdivided into three groups: precious opal, fire or red-yellow opal, and then common opal. The physical properties of each opal sub-group are dramatically different.
Pretty Wild Opal
Some of the more exciting opal varieties appearing in the couture corner are wood replaced opal. This type of fossilized material was at one time a large tree. When it fell, possibly in its watery grave, the right conditions of silica surrounding its landing encouraged opalized material to replace areas of the wood. The result – spectacular and exotic.
Another extravagant opal type cropping up with adventurous jewelers, known for their sculpture-art type of designs, are opalized dinosaur bone specimens. Australia is host to several regions where ancient water loving prehistoric creatures’ remains are buried and rare opalized materials are found there. Few collectors will ever have access to these oddities, however.
A Look inside the Stone
One trait all opals have in common is that they all contain various levels of hydration locked within their crystal structure. The water content ranges from 3 to 30%. All opal varieties, including fire opal, are a form of hydrous silicon dioxide. And their crystal structure is amorphous – unlike other gems we collect which have a cubic crystal structure. Opals’ tiny sphere-like crystals on the other hand are responsible for the unique impression of rainbow like plays of color, most dramatically displayed in the precious opal variety.
Heat it Up With Fire Opal
So what about the rest of us who love opal, and yearn for something distinctive, beautiful and – within reach? We especially are drawn to the exciting opal variety called Fire Opal.
Fire opals found in a wide range of warm hues have been collected for centuries according to numerous ancient accounts. Fire opal’s long history dates back to the 14th century. Early Mezzo American Aztecs gathered these eye catching stones. Still today, Mexican residents scour open pit quarries for them. Some people believe that the Mexicans bestowed its name, fire opal on this smolderingly hot gem. The ginger, cherry, and searing golden hues of fire opal keep these breathtaking jewels perennially popular.
So many deposits around the world produce fire opal: Brazil, Tanzania, Ethiopia, Mali, Guatemala, and of course Mexico.
The appearance of fire opal ranges from semi-translucent to transparent. Designers often select the dreamy look of semi-transparent fire opal to interpret their original designs. This is because the impression made with the semi-translucent fire opal adds a level of intrigue to their collection – leaving many people wondering, “What is this mysterious jewel?”
As Unique As You Are
Because fire opal has such a distinct persona, it’s selected by fine gem artists as a carving material. While other opals are often finished into cabochon cuts, fire opal is successfully faceted into lively brilliant gem shapes. The most saturated reds have added collectability as do highly transparent fire opals since these traits are more rarely occurring in nature. Each natural stone will have a bit of its own character to impart, and you will treasure your fire opal collection as much as early Aztec royalty did.
Award winning trade journalist and gemologist Diana Jarrett is also a Registered Master Valuer Appraiser and a member of the National Association of Jewelry Appraisers (NAJA). She’s a popular speaker at conferences and trade shows. Jarrett writes for trade and consumer publications, various online outlets, and for sightholders and other industry leaders.. Contact her at email@example.com, visit her website, www.dianajarrett.com, and/or follow her on FaceBook and Twitter (Loupey).