Gemstone Knowledge
Gemstone Knowledge from A to Z
Properties, color variations, and
characteristic features at a glance
A - Q
Amethyst
Amethyst is the best-known violet variety of the mineral quartz and has been prized since antiquity. Its color ranges from delicate lilac to deep purple, depending on the iron content and natural irradiation. Amethysts are robust, easy to cut, and versatile – both as a gemstone and a collector's item. A high-quality amethyst exhibits clear transparency and an intense, even hue.
Apatite
Apatite is a fascinating gemstone found in vibrant colors such as neon blue, green, and turquoise. Its vivid hues are created by traces of manganese or iron, making it popular with collectors and jewelry lovers alike. Although apatite is somewhat softer than many other gemstones, it impresses with its remarkable brilliance and variety. The rare Paraiba-like neon blue apatite is particularly sought after.
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Aquamarine
Aquamarine is the sky-blue to turquoise shimmering variety of the mineral beryl and is one of the most popular gemstones of all. Its clear, cool hue is reminiscent of seawater and looks particularly elegant in faceted cuts. High-quality aquamarines are characterized by transparency and a uniform, medium to strong blue tint. Thanks to its good hardness, aquamarine is excellently suited for jewelry and collections.
Garnet
Garnet is a diverse gemstone group that captivates with its strong natural colors and impressive brilliance. The spectrum ranges from fiery red to luminous orange, fresh green, or delicate rose tones – all without common treatments. Many garnets exhibit clear transparency, strong light reflections, and a natural, unadulterated radiance. Particularly popular are intense varieties such as tsavorite, rhodolite, spessartite, and demantoid.
Iolite
Iolite is a gemstone of transitions. Between blue and violet, light and shadow, it unfolds a fascinating depth that changes with every angle. Its pronounced pleochroism gives it a vibrant, almost mysterious radiance. Mostly untreated and always unique, iolite delights with its character, versatility, and quiet elegance.
Kunzite
Kunzite is the delicate pink to intensely fuchsia variety of the mineral spodumene and is valued for its elegant, often slightly violet hue. High-quality kunzites exhibit good transparency and fascinating light refraction, which is particularly showcased with the right cut. Due to its sensitivity to strong light, kunzite is usually preferred as an evening or collector's stone. Rare, intensely colored specimens are particularly sought after.
Opal
Opal is a unique gemstone known for its fascinating play of color. Unlike crystalline minerals, opal consists of microscopic silica spheres, which can refract light into spectacular colors. The color palette ranges from milky white to blue, green, and orange, all the way to intense red. Particularly high-quality opals display a vibrant, multi-colored iridescence, which is known as opalescence or play of color. Due to its exceptional optical properties, opal is one of the most fascinating gemstones for collectors, jewelry lovers, and admirers of natural works of art.
Peridot
Peridot is the bright green variety of the mineral olivine and is one of the few gemstones that occur exclusively in green. Its color ranges from yellowish to intense olive green and is caused by natural iron in the crystal. High-quality peridots show good clarity, vibrant color, and a characteristic, slightly oily brilliance. Due to its hardness, peridot is suitable for jewelry, collections, and decorative applications.
R - S
Ruby
Ruby is the intensely red variety of the mineral corundum and is one of the rarest and most valuable colored gemstones. Its famous color, often described as "pigeon's blood red," is caused by traces of chromium in the crystal. High-quality rubies show vibrant saturation, good transparency, and few inclusions, which makes them particularly desirable. Historically, rubies have been regarded as a symbol of passion, power, and protection.
Sapphire
Sapphire is the blue variety of the mineral corundum and is one of the most popular and valuable colored gemstones. Its hue ranges from delicate cornflower blue to deep midnight blue, depending on trace elements such as iron and titanium. High-quality sapphires exhibit clear transparency, strong saturation, and excellent brilliance. In addition to blue, rare colored sapphires (Fancy Sapphires) also exist, which are highly sought after by collectors.
Emerald
Emerald is the famous green variety of the mineral beryl and is one of the most valuable gemstones worldwide. Its deep green color is caused by chromium or vanadium and is considered one of the most coveted color spectrums in the gemstone world. Due to natural inclusions – the so-called Jardin – high-quality, clear emeralds are particularly rare. Intense color, good cut, and attractive transparency determine its value.
Spessartite
Spessartite, also known as spessartine garnet, is a vivid orange to reddish-orange gemstone with impressive brilliance. Its intense hues are caused by manganese in the crystal and range from light mandarin nuances to rich reddish-orange. High-quality spessartites exhibit strong light refraction, good transparency, and brilliant sparkle. Rare "Mandarin spessartites" from Namibia or Nigeria are particularly sought after.
Sphalerite
Sphalerite is an extremely brilliant gemstone, known for its exceptionally high dispersion—its fire even surpasses that of diamonds many times over. It displays vibrant hues from yellow to orange to red and brown, depending on the iron content in the crystal. Due to its comparatively low hardness, sphalerite is primarily valued as a collector's stone, where it impresses with its spectacular light refraction. Clear, intensely colored specimens are very rare and sought after.
Sphen
Sphene, also known as titanite, is a rare gemstone mineral particularly known for its exceptionally strong dispersion – its fire even surpasses that of diamond. It primarily occurs in fresh green and yellow hues and often exhibits a striking double refraction that enhances its brilliance. Due to its relative softness, sphene is primarily valued as a collector's stone or for jewelry with careful wear requirements. High-quality pieces with intense color and good clarity are very rare.
Spinel
Spinel is a gemstone with exceptional color purity and high brilliance, occurring in a wide spectrum – from vibrant red to cobalt blue to elegant gray tones. Deep red and rare blue spinels are particularly prized, a quality often not found in other gemstones. With excellent hardness, clarity, and natural beauty, spinel is an ideal jewelry and collector's stone that is increasingly gaining importance.
T - Z
Tanzanite
Tanzanite is a rare variety of the mineral zoisite, found only in Tanzania, and is known for its captivating blue-violet hue. The gemstones often exhibit distinct pleochroism, revealing blue, violet, or reddish nuances depending on the viewing angle. High-quality tanzanites impress with clear transparency, intense color, and good brilliance. Due to its extremely limited origin, tanzanite is among the most sought-after modern colored gemstones.
Topaz
Topaz is a versatile gemstone found in a wide range of colors – from clear white to golden yellow, blue, and rare pink. Particularly sought after are intensely golden-yellow "Imperial Topazes" and natural blue varieties. Thanks to its good hardness, strong brilliance, and attractive colors, topaz is excellent for jewelry and collections. High-quality specimens exhibit clear transparency and a precise cut.
Tsavorite
Tsavorite is a vivid green garnet and is one of the rarest and most valuable representatives of its mineral group. Its intense color is created by vanadium or chromium and often appears fresher and clearer than many emeralds. High-quality tsavorites exhibit excellent transparency, strong luster, and impressive brilliance. Due to their good hardness, they are suitable for both elegant jewelry and high-quality collections.
Tourmaline
Tourmaline is an exceptionally versatile gemstone, occurring in almost every color – from pure green and blue to pink, red, or dramatic bicolor varieties. Particularly sought after are Paraiba tourmalines with their vibrant neon blue, as well as intense pink to ruby-red rubellites. Tourmaline impresses with good hardness, brilliant light refraction, and enormous color diversity, which makes it popular among collectors and in jewelry design alike.
Zircon
Zircon is a natural gemstone with exceptionally high brilliance and strong dispersion, giving it a sparkling fire. It occurs in many colors, with clear, blue, and golden varieties being particularly popular. Unlike cubic zirconia (a synthetic product), zircon is a genuine, geologically ancient mineral with impressive density and refractive index. High-quality zircons exhibit clear transparency, precise cut, and vibrant hues.