Phosphosiderite

Phosphosiderite Crystal

Phosphosiderite is a rare iron phosphate mineral (FePO4·2H2O) with a soft, orchid-like lavender to rose-purple color. It has a Mohs hardness of 3.5-4, a vitreous to resinous luster, and a color intensity that stops collectors mid-scroll. The mineral was first described in 1890 and named for its chemical components: phosphorus and iron (Greek sideros).

The most sought-after phosphosiderite comes from Peru, where it occurs in iron-rich phosphate deposits in the Andes. Chilean and Argentine specimens also appear in the market. Phosphosiderite's lavender color is unusual in the mineral world — few minerals achieve this specific soft, warm purple-pink without dyeing or treatment. The color comes from the iron content interacting with the phosphate structure.

This collection features polished slabs, palm stones, tumbled stones, and cabochons. Phosphosiderite pairs beautifully with lepidolite, amethyst, and charoite for a lavender-toned display. Browse our Collector's Edition for more rare specimens. Free shipping on all U.S. orders over $150.

Frequently Asked Questions

What is phosphosiderite?

Phosphosiderite is a rare iron phosphate mineral (FePO4·2H2O, Mohs 3.5-4) with a distinctive lavender to rose-purple color. First described in 1890, named for its phosphorus and iron content. Most gem-quality material comes from Peru.

Why is phosphosiderite lavender?

The lavender color results from iron (Fe3+) within the phosphate crystal structure. This particular combination produces a warm purple-pink that is unusual in the mineral world — very few natural minerals achieve this specific shade without dye or treatment.

Is phosphosiderite rare?

Yes. Phosphosiderite is uncommon as a gem-quality mineral. While it occurs in various phosphate deposits worldwide, attractive lavender specimens suitable for polishing and collecting come primarily from Peru. It is not widely known outside collector circles, which is part of what makes it a distinctive addition to any collection.

How do I care for phosphosiderite?

Phosphosiderite is soft (Mohs 3.5-4) and should be treated as a display mineral. Store separately from harder stones. Clean with a soft dry cloth — avoid water on raw specimens as it is a hydrated mineral. Handle polished pieces carefully as edges can chip. Keep away from direct sunlight for extended periods.

What other minerals look like phosphosiderite?

Lepidolite and amethyst share purple tones but look quite different in person. Lepidolite is a mica with a sparkly, flaky texture. Amethyst is harder (Mohs 7) and more transparent. Sugilite is another rare purple mineral but is opaque and darker. Phosphosiderite's warm orchid-lavender is distinctive among purple minerals.