Purple stones captivate with their rich and diverse hues, from soft lavenders to deep violets. Their beauty makes them a popular choice for collectors, jewelry, and various adornments.
Prominent Purple Gemstones
Amethyst, a violet variety of quartz, ranges from light lavender to deep royal purple, sometimes with red or blue tones. Found in volcanic geodes, notable sources include Brazil, Uruguay, Siberia, and Sri Lanka. It is widely used in jewelry.
Lepidolite presents a delicate purple, often appearing in shades of lilac, pink, or gray. This lithium-rich mica mineral forms in granitic pegmatites and is frequently used for beads, cabochons, and ornamental carvings.
Charoite features swirling patterns of white, gray, and brown against lilac or deep violet. Its unique fibrous structure is exclusively found in Siberia, making it popular for jewelry and decorative items.
Sugilite ranges from deep royal purple to lighter lavender or lilac, its color from manganese content. Significant deposits are in South Africa, Japan, Canada, Australia, and India. It is used for jewelry cabochons, beads, and decorative objects.
Fluorite frequently exhibits purple or lilac hues due to impurities. It often forms well-defined cubic or octahedral crystals. Though primarily a collector’s stone, it can be used in jewelry with care due to its softness.
Tanzanite, known for its blue-violet pleochroism, owes its color to trace vanadium. Almost exclusively found in Tanzania, it is used in high-end rings, pendants, and earrings.
Purple sapphire, a variety of corundum, has rich, deep purple coloration. This durable gemstone is a popular choice for fine jewelry.
The Origin of Purple Coloration
Purple color in stones arises from specific atomic interactions within their crystal structures. One common mechanism is trace elements, small quantities of other elements incorporated during formation. For instance, amethyst’s purple is primarily due to iron ions (Fe3+) within the quartz lattice. These iron impurities absorb certain light wavelengths.
Manganese is a trace element responsible for purple hues in stones like lepidolite, sugilite, and charoite. Vanadium causes the blue-violet color of tanzanite. These elements act as chromophores, selectively absorbing parts of the visible light spectrum.
Beyond trace elements, “color centers” contribute to a stone’s purple appearance. These are structural defects within the crystal lattice that trap electrons and interact with light. In amethyst, for example, natural irradiation causes iron ions to lose an electron, forming color centers that absorb yellow and green light, producing purple.
Distinguishing Purple Stones
Differentiating purple stones involves observing physical properties. Hardness is a primary indicator, assessed by scratching. Amethyst rates 7 on the Mohs scale. Fluorite is softer at 4, and lepidolite is 2.5 to 4, making them scratchable by a steel nail or copper coin.
Luster, how light reflects off a stone’s surface, provides clues. Many purple gemstones have a vitreous or glassy luster. Lepidolite and charoite can exhibit a pearly or silky sheen due to their fibrous or scaly structures. Clarity and transparency vary; amethyst is typically transparent to translucent, while sugilite and charoite are often translucent to opaque.
Specific gravity, a stone’s heaviness for its size, can assist in identification, though it requires specialized tools. Unique patterns, like charoite’s swirling textures or fluorite’s subtle internal growth lines, are also indicators. These methods offer practical ways to distinguish purple stones.