When it comes to crystals, green and blue colors are quite common. There are a number of different crystals that exhibit these color combinations to varying degrees. Some crystals may display dark forest greens, sea greens, aqua blues or deep royal blues. The specific colors and shading depends on the mineral composition, presence of additional elements and optical phenomena. So which crystals typically display both green and blue hues? Let’s take a closer look at some of the main options.
Green and Blue Beryl Varieties
Some of the most well-known green and blue crystals belong to the beryl family. Beryl is a mineral that contains beryllium, aluminum, silicon and oxygen. The varied chemical composition of different beryl stones results in an array of green and blue color varieties.
Aquamarine
Aquamarine is a light blue or cyan version of beryl. It gets its icy blue colors from trace amounts of iron. The name comes from the Latin term for seawater. Aquamarine crystals can exhibit various shades of blue, from almost clear sky blue to deeper turquoise hues. Darker blue aquamarine may appear to have a very slight greenish cast when viewed from certain angles.
Emerald
Emerald is the deep green variety of beryl. Its rich verdant color comes from trace amounts of chromium and/or vanadium. Top quality emeralds display a vivid bluish-green hue. Unlike aquamarine, emeralds rarely have tints of blue. However, at certain angles, some emerald specimens may show very faint hints of blue—a telltale sign of their beryl mineral lineage.
Green and Blue Tourmaline
Like beryl gems, tourmaline also occurs in an array of green and blue varieties. Tourmaline is a complex borosilicate mineral that comes in every color of the rainbow. The specific hue depends on the interaction of the tourmaline’s chemical composition with light waves.
Green Tourmaline
Green tourmaline can display the whole range of lush green shades. Minty pastel greens, rich olive tones, vibrant forest greens and more are possible. Green tourmaline gets its verdant colors primarily from iron. However, trace elements like chromium and vanadium can also influence the specific hue.
Blue Tourmaline
Blue tourmaline includes icy pastel blues, vivid azure colors and deeper indigo tones. The blue color comes from the interaction of iron ions with light waves. In strong light, blue tourmaline may also exhibit a slightly greenish secondary hue.
Green and Blue Kyanite
Kyanite is an aluminum silicate mineral known for its distinctive bladed crystal habit. It occurs in a range of green and blue colors.
Green Kyanite
Green kyanite is colored by trace amounts of chromium. It ranges from yellowish-greens to deep emerald hues.
Blue Kyanite
Blue kyanite gets its color from iron impurities. It forms in various shades of blue including sky blue, teal blue-green, deep sapphire blue and indigo. Blue kyanite may display a faint greenish tinge in certain lighting.
Other Green and Blue Gemstone Options
While beryl, tourmaline and kyanite cover some of the best known green and blue crystals, there are a few other mineral options that occur in these colors:
Smithsonite
Smithsonite is a carbonate mineral that forms botryoidal clusters. Its blue-green colors come from copper inclusions.
Apatite
Green and blue apatite gets its color from trace amounts of iron, manganese and other elements. It forms in hues ranging from sea green to sky blue.
Sodalite
Sodalite is an alkali chloride mineral best known for its blue color. Trace amounts of iron impart a greenish tint in some sodalite.
Chrysocolla
This hydrated copper silicate forms in vibrant blue and blue-green shades. Its color comes from copper inclusions.
Variscite
Variscite is a hydrated aluminum phosphate that occurs in yellow-greens, sky blues and teal shades.
Green and Blue Agate
While less common than banded agates, some forms of green and blue agate exist. These agates get their color from trace minerals.
What Influences Crystal Color?
What makes crystals green and blue? As we’ve seen, small amounts of transition metals and trace elements have a significant impact on crystal coloration. But how exactly do these impurities interact with light to produce such vivid hues? The key factors are:
Chemical Composition
The exact chemical formula of the crystal influences how impurities are incorporated into the atomic structure. This affects how the material absorbs and transmits specific light wave frequencies to produce color.
Oxidation States
The oxidation state of transition metals like chromium, iron, copper etc. present in trace amounts impacts crystal color. Different oxidation states produce different energies that interact with light waves to create various colors.
Color Centers
Point defects in a crystal lattice where ions are missing or replaced are called color centers. These disrupt the spacing and symmetry in the structure. When electrons move between color centers, they absorb photons of certain energies, resulting in perceived color.
Optical Phenomena
Optical effects like light scattering, diffraction, pleochroism and interference of light waves can also influence crystal color. Certain minerals change color based on the angle from which they are viewed.
How Can You Identify Green and Blue Crystals?
Identifying unknown green and blue crystals takes some detective work. Here are some tips:
Consider Basic Properties
Note factors like crystal shape, structure, hardness, density, cleavage etc. This helps narrow down the possibilities. For example, emerald’s hexagonal crystals point to it being a form of beryl.
Examine Under Magnification
Use a loupe or microscope to look for small inclusions, growth patterns and other identifying visual clues. For instance, tourmaline’s striations are indicative of its trigonal crystal system.
Conduct Diagnostic Tests
Advanced tests can confirm a specimen’s specific chemical composition. For example, aquamarine and emerald can be verified as beryl varieties with chemical analysis.
Consider Optical Properties
Factors like pleochroism, refractive index, fluorescence and more when viewed under lamps and scopes can also help identify blue-green crystals. For example, kyanite’s anisotropic nature helps distinguish it.
| Crystal | Chemical Formula | Color Cause |
|---|---|---|
| Aquamarine | Be3Al2Si6O18 | Iron |
| Emerald | Be3Al2Si6O18 | Chromium/Vanadium |
| Green Tourmaline | NaFe3Al6(BO3)3Si6O18(OH)4 | Iron, Chromium, Vanadium |
| Blue Tourmaline | NaFe3Al6(BO3)3Si6O18(OH)4 | Iron |
How are Green and Blue Crystals Used?
Thanks to their mesmerizing colors and metaphysical associations, green and blue crystals are popular for various applications:
Jewelry
Aquamarine, emerald, blue topaz and green tourmaline are valued gemstones used extensively in jewelry. They make beautiful rings, pendants, bracelets and more.
Ornaments
Bright blue kyanite blades or drusy green smithsonite clusters make striking mineral specimen ornaments. They are popular for home decor and display pieces.
Carvings
Green jade and emerald are ideal for intricate figurines and carvings. Their hardness allows superb detail and polish.
Metaphysical Uses
Green and blue crystals like emerald and blue lace agate are associated with calming, healing properties. They are commonly used for crystal healing practices.
Industrial Applications
Emerald’s hardness makes it useful for applications like laser optics. Chrysocolla is sometimes used as a minor ore of copper.
Conclusion
In summary, there are a variety of minerals that form in green and blue crystal varieties. Chemical composition and trace elements impart these colors through complex interactions with light. Aquamarine, emerald, green and blue tourmaline, kyanite, smithsonite, apatite, sodalite, chrysocolla, variscite and some agates exhibit these beautiful bichroic hues. Understanding the science behind crystal color helps identify unknown specimens. These vibrant green and blue crystals are treasured in jewelry, decor, carvings, spiritual practices and more. Their eye-catching colors and mystical allure give them widespread appeal.
