Red Opal: Very Rare Opal Color

Red opal is a rare variety of precious opal with a body color dominated by red hues, with minimal orange or yellow tones. Red Opal is one of the rarest opal colors, along with black opal.

Red Opal: Rare Opal Color

Red opal with play-of-color signifies a gemstone that exhibits both a rare red body color and the mesmerizing play-of-color effect. This combination makes it a highly sought-after gem by collectors and jewelry enthusiasts.

Play-of-color: A unique optical phenomenon seen in precious opals, where the stone diffracts light, causing flashes of vibrant colors to appear as the opal is moved.

Red Opal: Very Rare Opal Color

Red opal belongs to the mineraloid group, characterized by its amorphous structure. Chemically, it primarily comprises silicon dioxide (SiO₂·nH₂O), commonly known as silica, along with varying amounts of water molecules. The presence of trace elements such as iron oxide contributes to the gemstone's red coloration.

Unlike crystalline minerals, opal lacks a defined crystal lattice. Instead, it forms through the deposition of silica spheres in a three-dimensional arrangement. This unique structure results in the gem's distinctive play-of-color phenomenon, where vibrant hues dance across its surface when exposed to light.

Properties of Red Opal

• Color: Red opal can range in color from a fiery reddish-orange to a deep, almost crimson red. The rarest variety has a pure red color with minimal orange or yellow tones.
• Hardness: Like other opals, red opal has a Mohs hardness of 5.5 to 6.5, making it relatively delicate and susceptible to scratches.
• Luster: Vitreous to greasy
• Transparency: Can range from translucent to transparent
• Specific gravity: 1.9-2.3
• Refractive index: 1.40-1.45

Where is red opal found?

While the exact locations of exceptionally rare red opals with play-of-color are elusive, there are places where red opals, including those with a fiery body color, can be found. These locations generally align with known sources of fire opals:

• Mexico: Querétaro, Jalisco, and Guerrero are all known sources of fire opals, which can sometimes exhibit a reddish hue.
• United States (Oregon): Fire opals, particularly those with a red body color, have been found in the Ochoco Mountains of Oregon.
• Australia: Although Australia is famous for its white opals with play-of-color, there have been recent discoveries of fire opals in the country. These fire opals may range from orange-red to deeper red tones.
• Ethiopia: Ethiopia is a relatively new source of opals, and some fire opals with a reddish body color have been found there as well.

Rare red opal from Lightning Ridge, Australia Photo: Sedaopals

 Red Opal Vs Fire Opal

The key differences between red opal and fire opal

Red Opal: A rare variety with a body color ranging from fire engine red to blood red. Red opal can exhibit some play-of-color, but it's not the defining characteristic.

Fire Opal: Transparent to translucent with a body color typically in yellow, orange, or red. Fire opal typically does not show play-of-color. Its beauty comes from its inherent fiery body color.

Red opals can sometimes be called fire opals, particularly if they have a strong orange or yellow body color along with red hues. Fire opal is sometimes referred to as "Mexican opal" because of its prominent source in Mexico.

Rough Red Opal, from Welo, Ethiopia