What is autunite?
Autunite is a hydrated calcium uranium phosphate and a well-known secondary uranium mineral. Its yellow-green colour and fluorescence make it visually distinctive, but every specimen should be treated as radioactive and handled as a sealed display object.
Mineralogy and structure
Autunite is commonly represented by Ca(UO2)2(PO4)2·10-12H2O and has an orthorhombic structure in the standard reference form. Mohs hardness is only 2-2.5 and density varies with hydration. The mineral may dehydrate toward related phases.
Colour and appearance
Yellow, greenish-yellow and pale green colours are typical. Crystals are thin to thick tabular, foliated or scaly, and surfaces may have pearly, waxy or resinous lustre. Many specimens fluoresce bright green under suitable ultraviolet light.
Formation and localities
Autunite forms by oxidation and hydration of primary uranium minerals, especially in granite-related deposits and near-surface fractures. The type locality is near Autun in France; important material is also known from Portugal, the United States, Germany and the Czech Republic.
Collection and safety
Autunite is fragile and radioactive. Store it sealed, minimise handling, keep it away from living spaces and food, and follow local guidance for radioactive mineral collections. Do not cut, grind or polish it.
Autunite and zodiac signs
In popular birthstone and zodiac guides, Autunite is often associated with Scorpio and Aquarius. These zodiac crystal associations are part of modern spiritual culture and vary between traditions, countries and individual practitioners. They are not a mineralogical classification and should not be presented as a scientific property of the stone.
Esoteric meaning of Autunite
Crystal collectors and readers of esoteric symbolism may choose Autunite for its colour, texture, locality and personal meaning. In crystal healing and meditation traditions, it may be described with themes such as focus, grounding, protection, calm or confidence, depending on the source. These symbolic interpretations can be useful for storytelling and personal reflection, but there is no reliable scientific evidence that a mineral changes health, energy, luck or destiny.
Choosing Autunite as a birthstone or symbolic crystal
When choosing a Autunite birthstone, zodiac crystal or spiritual gift, compare the actual specimen: natural colour, crystal habit, transparency, inclusions, locality and condition. A mineral guide is more reliable when symbolic associations are kept separate from tested physical properties and from the description of an individual piece. Because Autunite may contain toxic or radioactive elements, it should remain a display specimen and should never be cut, polished, used in jewellery or treated as a wellness product.
