On January 11th, National Jeweler, posted a story entitled “Precious gems found in Detroit fish tank.”
An old fish tank there was found to be full of faceted and unfaceted gems. A gemologist told police that three of the stones alone could be worth more than $100,000.
A video on clickondetroit shows an emerald from the tank gravel appraised at $35,000 and a so-called Kashmir sapphire appraised at $40,000-$50,000. It’s not surprising that they ended up in a fish tank; they look semi-opaque. Emeralds, sapphires and rubies with no transparency normally have little value, which explains why the starting auction bid for these stones is $5.
On the other hand, stones such as transparent green zoisite can be as expensive as tanzanite (the trade name for blue to purple zoisite). In order to differentiate transparent from non-transparent green zoisites, dealers call the transparent varieties green tanzanites. An example of green tanzanite is shown in photo 1. Compare it to the green zoisite pedestal in photo 2. The value of the ruby frog and green zoisite is primarily determined by the artistic value of the carving, not by the intrinsic value of the semi-opaque ruby material and zoisite.
Transparency and clarity are often interconnected, but they’re not the same. A stone can be transparent like crystal, yet have a low clarity. Likewise a gem may be flawless, yet be translucent. Even though transparency can have a significant impact on price, lab documents seldom include it as a price factor. However, often on identification reports, labs list transparency in the description of the stone.
Some of the rubies, sapphires and emeralds identified as transparent, though, are not transparent. This is one of the reasons why it is important to look at gems before you buy them. Don’t neglect to judge their transparency; if you do, you could end up believing that a $5 stone could be worth $50,000.
You can learn more about transparency and other value factors in my book Exotic Gems, Volume 1: How to Identify and Buy Tanzanite, Ammolite, Rhodochrosite, Zultanite, Sunstone, Moonstone & other Feldspars.
Los Angeles, USA. January 2011
Transparent green zoisite by Wimon Manorotkul
Ruby and zoisite carving by Renée Newman
Video capture courtesy of ClickOnDetroit.com
Disclaimer – The AIJV blog is authored by a selection of AIJV members and guests specifically to be able present many different viewpoints on a large variety of subjects. The opinons expressed by the authors are not necessarily those of the AIJV.