Your Purchases
Water opal is a transparent to translucent variety of hydrophane opal that exhibits remarkable optical properties when immersed in water, displaying enhanced play-of-color and transparency due to its porous microstructure. The stone, composed of amorphous silica dioxide with varying percentages of water content, belongs to the mineraloid class of gemstones.
This distinctive gem transforms from an opaque, often whitish appearance in its dry state to a transparent or semi-transparent state when saturated with water, owing to its unique molecular structure that allows water molecules to fill microscopic voids within the stone. The phenomenon occurs because the refractive index of water matches more closely with the opal’s silica structure than air does, reducing light scattering and revealing the stone’s internal play-of-color. Water opals typically originate from deposits in Mexico, particularly the Magdalena region, where specific geological conditions create their distinctive porous characteristics.
Water opal is typically a natural gemstone.
Common names for Water opal include Hyalite, Muller’s Glass, and Muller’s Opal.
Water opal has a hardness of 5.5 to 6.5 on the Mohs scale, which makes it somewhat susceptible to scratches and abrasion.
The refractive index of water opal ranges from 1.44 to 1.46, which is relatively low compared to many other gemstones.
Water opal exhibits a vitreous to subvitreous luster, giving it a glass-like appearance that is particularly noticeable when well-polished.
This type of opal typically does not exhibit any cleavage, which is a common characteristic of opals in general.
Water opal has a conchoidal fracture, which is a smooth, curved surface that resembles the shape of a seashell.
The specific gravity of water opal is typically around 1.9 to 2.3, which is relatively low, indicating a less dense material.
Water opal does not exhibit double refraction; it is an isotropic gemstone.
Water opal generally shows little to no dispersion or “”fire,”” which refers to the gemstone’s ability to disperse light into the colors of the spectrum.
The crystal system of water opal is amorphous, meaning it lacks a defined crystalline structure.
Water opal can range from colorless to a pale milky hue. It may also display play-of-color (iridescent flashes of color), depending on the conditions under which it was formed.
This gemstone ranges from transparent to translucent, enhancing its appeal and making it suitable for various types of jewelry.
Water opal does not display pleochroism due to its isotropic nature.
Some water opals may fluoresce under UV light, typically showing a white or pale green glow, but this can vary.
Opal is generally considered to have fair to poor toughness due to its brittleness and natural inclusions that may weaken the stone.
Water opal is brittle, which is typical for opals, making them more susceptible to damage from impact.
Being isotropic, water opal exhibits a single refractive index with no optic sign.
Water opal does not generally display a distinctive absorption spectrum due to its amorphous crystal structure and transparency.
Water opal is a form of silica (silicon dioxide, SiO2) and includes significant amounts of water (up to 21% by weight in some cases).
While not common, some specimens of water opal may exhibit a cat’s eye effect if they contain aligned fibrous inclusions.
Asterism is not typically observed in water opal due to its amorphous structure and lack of the necessary inclusions.
The play-of-color seen in some water opals is a type of iridescence caused by the diffraction of light passing through microscopic silica spheres within the gem.
Water opal is not magnetic.
Being composed mainly of silica, water opal is a poor conductor of electricity.
Water opal is not radioactive.
Water opal, with its subtle beauty and fascinating properties, offers a unique option for jewelry enthusiasts and collectors alike. Its care should be handled delicately due to its softer and more brittle nature compared to harder gemstones.
