Dumortierite Tumbled Gemstone

Non-toxic and durable to handle. As with most polished stones, avoid prolonged soaking, harsh chemicals, and hard knocks that can chip cut pieces.

Dumortierite forms deep in the earth under sustained heat and pressure, crystallizing in aluminum-rich metamorphic rocks, pegmatites, and coarse granites. Rather than growing as showy single crystals, it assembles itself from countless microscopic fibers packed into dense, radiating masses, strength built quietly, one thread at a time. Named in 1881 after Eugene Dumortier, it is drawn today from deposits in Brazil, Madagascar, Nevada, Austria, and beyond.

Dumortierite is an aluminum borosilicate with the approximate formula Al7(BO3)(SiO4)3O3, crystallizing in the orthorhombic system. It usually occurs as fibrous, columnar, or radiating aggregates rather than distinct crystals, ranging from deep blue and violet-blue to purple, pink, and reddish-brown. It shows a vitreous to silky luster, is strongly pleochroic, and has a specific gravity near 3.3 to 3.4. Massive material is hard and tough and takes an excellent polish, which suits it well to cabochons and beads.

• Described only in 1881 and named for French paleontologist Eugene Dumortier, dumortierite is far too young to carry genuine antique legend; its lore is entirely modern.
• Its dense denim-blue has long caused it to be mistaken for or sold as lapis lazuli and sodalite, earning fibrous specimens the nickname denim lapis.
• In contemporary crystal tradition it is called the Stone of Patience, linked to Archangel Michael and used to steady the mind during study, writing, and long undertakings.