Hawk's Eye - Tiger Eye’s Grey Brother

There are all sorts of gemstones out there. Not surprisingly, many of these gemstones are somewhat related to each other, because they are often simply varieties of the same mineral. One such gemstone is Hawk's Eye, which we affectionately recognize as Tiger Eye’s grey brother.

Hawk's Eye is a blue-grey to blue-green gemstone mostly composed of microcrystalline quartz, or chalcedony. Unlike most chalcedony varieties, hawk's eye is a rock, not a mineral.

This special variety is achieved through the pseudomorph nature of Hawk's Eye. "Pseudomorph" refers to a stone that has replaced part of another mineral over long periods of time. Hawk's Eye is a pseudomorph of macrocrystalline quartz. It began life as the mineral crocidolite and slowly transformed into Hawk's Eye over time.

Crocidolite is one of the many forms of asbestos, and it has a blue, fibrous composition. It gradually achieves the pseudomorph transformation when quartz begins to embed itself between those fibers, slowly replacing the entirety of the gemstone while still maintaining its shape and texture.

Hawk's Eye Sources

Hawk's Eye has many sources across the world, including Burma, Spain, South Africa, Australia, China, and many others. But the most significant deposits are located in Thailand and the Northern Cape province of South Africa, the two largest commercial suppliers of Hawk's Eye stones.

Hawk's Eye and Tiger's Eye

Ironically, rather than calling Tiger's Eye the brother of Hawk's Eye, it may be more accurate to say that Hawk's Eye is the parent of Tiger's Eye. After all, Tiger's Eye actually starts as Hawk's Eye.

The transformation of crocidolite to quartz leaves behind oxide; if there is minimal iron left over, you get the typical blue of the transformation, but more iron results in the golden brown color that defines Tiger's Eye. In the end, they are simply variants of the same thing.

That said, one of the biggest distinctive differences between Hawk's Eye and Tiger's Eye is their colors. While Tiger's Eye is a distinctive brownish gold, Hawk's Eye is more grayish blue. As explained earlier, Hawk's Eye also has less iron in it than Tiger's Eye, hence the color it has.

Pictured above: Tiger's Eye on the left, Hawk's Eye on the right

Still, when considering Hawk's Eye, it’s important to keep in mind that they are often a variety of different colors, and even though they tend to be primarily bluish-gray or blue-green, they can still have notable streaks of golden brown in them. The stones themselves often bear multiple colors across their surface regardless. Whether or not this affects their worth is up to the individual’s personal preference, but the presence of gold or brown in Hawk's Eye does not indicate defectiveness in any way. Streaks of golden brown are usually the result of a slightly higher level of iron in that particular area.

For the record, the majority of Hawk's Eye gemstones are not treated in any way. However, some can be dyed for darker colors, or treated with nitric acid to lighten their colors. Gem dealers will almost always notify you if such enhancements have been used on a Hawk's Eye gemstone, but if you need extra peace of mind, you can always ask.

SHOP FOR TIGER'S EYE & HAWK'S EYE

Tiger Eye