Introduction to Gemology: Getting to Know the Other Blue Gemstones

When it comes to blue gemstones, sapphire, lapis lazuli and blue diamond are the most commonly known. Blue gemstones make beautiful adornments and are used by some people for their calming properties. This article, however, doesn´t focus on the popular blue gems. Instead it lists and describes five lesser- known blue gemstones: agate, azurite, and benitoite.

Say blue gemstones and people would immediately think of sapphire and lapis lazuli

as these two are the most commonly known blue gemstones. Of course, there is

always the blue diamond crystal, which is one of the most coveted and expensive

gems in the world. Some other blue gemstones exist but are less popular because

they may be so rare or kept concealed from the public. Or, they may be of the cheaper

variety. Still, they are gems that can beautifully adorn any piece of jewelry.

The Lesser-Known Blue Gemstones

* Agate

Among the blue gemstones that are not so well-known is the agate. It is essentially

crystalline quartz characterized by bands made of chalcedony layers that form in rock

crevices. The classification of agate varieties is based on appearance, characteristics,

or source. Agate can be found in abundance in many places. Its varieties include the

Botswana agate, Brecciated agate, agate-jasper, crazy lace agate, and blue lace

agate.

Agate had been in use since the Middle Ages and people then believed that this blue

gemstone could improve a person’s eyesight and character. According to an 1864

publication, The Book of Seven Leechndoms, the therapeutic benefits of agate include

protection from poison, drunkenness, thunder, sorcery, and demonic possession.

* Azurite

Another blue gemstone worthy of note is the azurite. It is often mistaken for lapis lazuli

or other kinds of blue gemstones. Azurite and green malachite are usually found

together because azurite turns into malachite due to weathering of the specimen surface into malachite.

Azurite is used occasionally as beads and as jewelry, and also as an ornamental stone. However, its softness and tendency to lose its deep blue color as it weathers limit such uses. Heating destroys azurite easily, so all mounting of azurite specimens must be done at room temperature.

* Benitoite

Benitoite is a rare blue gemstone, found in hydrothermally altered serpentinite. Benitoite fluoresces under short wave ultraviolet light, appearing light blue in color.

It was first described in 1907 by George D. Louderback, who named it benitoite, “as it occurs near the head waters of the San Benito River in San Benito County,” California.