Aventurine gemstone and color formation

Aventurine is a variety of translucent poly-crystal quartz with inclusions of minerals.  It is fundamentally different from Amethyst which is also a variety of quartz with the presence of manganese and iron in quartz, the manganese and iron are impurities in atomic level to form new energy states (color centers) that produces the purple color. In Aventurine case, the inclusions of minerals are much larger particles which reflect light that enters the quartz and produce a sparkly appearance.  The common color of aventurine is green and red orange, but it may also be brown, yellow, blue, or purple.

Green aventurine is a variety of translucent poly-crystal quartz with inclusions of Fuchsite, also known as chrome mica, is a chromium (Cr) rich variety of the mineral muscovite, belonging to the mica group of phyllosilicate minerals, with the following formula: K(Al,Cr)₂(AlSi₃O₁₀)(OH)₂, which display apple green color.  Bright reflection light from apple green Fuchsite inclusions inside quartz produce a sparkly silvery green appearance for green aventurine.

For red orange and brown aventurine, the colors are attributed to inclusions of red orange hematite and brown hematite inside quartz.  Hematite is the mineral form of iron oxide (Fe₂O₃), colored black to steel or silver-gray, brown to reddish brown, or red.  Bright reflection light from red orange hematite or brown hematite inclusions inside quartz produce a sparkly red orange and brown appearance for red orange and brown aventurine.

For yellow aventurine, the colors are attributed to inclusions of Pyrite. The mineral pyrite, or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula FeS₂. This mineral's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold. Bright reflection light from golden Pyrite inclusions inside quartz produce a sparkly yellow appearance for yellow aventurine.

For blue aventurine, the colors are attributed to inclusions of blue Dumortierite . Dumortierite is a fibrous variably colored aluminium boro-silicate mineral, Al₇BO₃(SiO₄)₃O₃.  The crystals are varied in color from brown, blue, and green to more rare violet and pink. Substitution of iron and other tri-valent elements for aluminium result in the color variations. Bright reflection light from blue Dumortierite inclusions inside quartz produce a sparkly blue appearance for blue aventurine.

For purple aventurine, the colors are attributed to inclusions of purple Lepidolite.  Lepidolite is a lilac-gray to rose-colored member of the mica group with formula K(Li,Al,Rb)₃(Al,Si)₄O₁₀(F,OH)₂. Bright reflection light from purple Lepidolite inclusions inside quartz produce a sparkly purple appearance for purple aventurine.

The majority of green and blue-green aventurine originates in India. Creamy white and red orange material is found in Chile, Spain and Russia.

Aventurine is a popular gemstone because of its beauty and also because it is not highly priced.  Aventurine is formed into gemstone beads for jewelry making.