Citrine

Hardness: 7 on the Mohs scale. Color: Commonly yellow, but can range from colorless to brown, orange, red, green, blue, or purple. Luster: Vitreous (glassy). Crystal Structure: Trigonal. Rarely shows cleavage. Specific Gravity: 2.65.

Citrine is a variety of quartz. It forms hydrothermally in igneous and metamorphic rocks, as well as in pegmatites. The yellow color is due to the presence of iron impurities within the quartz crystal lattice. While natural citrine is rare, it can form over millions of years under specific geological conditions. Heat treatment of other quartz varieties (like amethyst) can accelerate the color change. Most natural citrine forms at relatively low temperatures.

Citrine is primarily used as a gemstone in jewelry, including rings, necklaces, earrings, and bracelets. Due to its durability (Mohs hardness of 7), it is suitable for everyday wear. It is also collected by mineral enthusiasts. In some belief systems, citrine is associated with prosperity and positive energy.

Citrine is often confused with topaz. Much of the citrine on the market is actually heat-treated amethyst or smoky quartz, as natural citrine is quite rare. The name 'citrine' comes from the French word 'citron,' meaning lemon, due to its common yellow color. It is a popular gemstone for its attractive color and durability.

In the field, natural citrine can be identified by its color, hardness (it can scratch glass), and vitreous luster. It often occurs as crystals within vugs or veins in granitic rocks. Major sources of natural citrine include Brazil, Bolivia, Uruguay, and Madagascar. When identifying, look for natural color zoning or subtle inclusions that differentiate it from heat-treated amethyst, which often has a reddish tint or 'hot spots' of color intensity. Heat-treated material can also fade with prolonged exposure to sunlight.