• Chemical Formula: (Y, Ca, Fe, Th)(Ti, Nb)2(O, OH)6, Yttrium Calcium Iron Thorium Titanium Niobium Oxide Hydroxide.
  • Class: Oxides and Hydroxides
  • Uses: A very minor ore of rare earth elements and as mineral specimens.
  • Specimens

Aeschynite is one of several Rare Earth Oxides and has two synonyms; "blomstrandine" and "priorite". Aeschynite's nomenclature is even more complex than this however. There are no less than three mineral names that begin with aeschynite and a few others that use aeschynite in their names. These minerals are all officially distinct minerals, but actually just differ in their respective compositions. The structure of these minerals is more or less unchanged. The prefixes or suffixes indicate which rare earth metal is predominant in the mineral as illustrated below:

  • Aeschynite-(Y) the yttrium rich aeschynite.
  • Aeschynite-(Ce) the cerium rich aeschynite.
  • Aeschynite-(Nd) the neodymium rich aeschynite.
  • Niobo-aeschynite-(Ce) the rich niobium/cerium aeschynite.
  • Tantalaeschynite-(Y) the tantalum/yttrium rich aeschynite.

Aeschynite referenced in guides and texts without any qualifiers usually refers to aeschynite-(Y) as it does here.

Rare Earth Oxides such as aeschynite form from the leftover elements that other minerals seem to not want. Other rare earth oxides such as fergusonite, samarskite and euxenite have very similar properties to aeschynite and are often associated with each other, compounding the problem. Even the common oxide, rutile, is almost indistinguishable from these rare earth oxides without chemical tests when rutile is found massive.

Aeschynite is found in rare earth rich granite pegmatites, a slow cooling igneous intrusive rock. Aeschynite is associated with minerals such as quartz, feldspars, zircon, columbite, xenotime, monazite, tantalite and other rare earth minerals. Aeschynite forms well shaped crystals at times, is associated with other rare minerals and can be an interesting specimen in someone's collection.


  • Color is black to dark brown or yellowish brown in smaller crystals.
  • Luster is vitreous to adamantine or pitchy when more massive.
  • Transparency: Crystals are nearly opaque in massive forms and translucent in small crystals.
  • Crystal System is orthorhombic; 2/m 2/m 2/m
  • Crystal Habits include tabular to prismatic almost blocky crystals, some with well formed domal terminations. Often embedded in the matrix of the host pegmatite; as well as granular and massive.
  • Cleavage is absent.
  • Fracture is conchoidal.
  • Hardness is 5 - 6
  • Specific Gravity is approximately 4.9 - 5.1 (heavy for non-metallic minerals).
  • Streak is reddish brown or reddish yellow.
  • Other Characteristics: Weathered crystals/specimens are often coated with a limonite like earthy coating.
  • Associated Minerals include quartz, feldspars, euxenite, fergusonite, monazite, columbite, tantalite, allanite, gadolinite, xenotime and zircon.
  • Notable Occurrences include the Ural Mountains of Russia; Urstad, Hittero, Norway and Madagascar.
  • Best Field Indicators are luster, fracture, color, streak, associations, environment and specific gravity.
AESCHYNITE specimens:
(hover for more info)
AESCHYNITE specimen aes-1
$ 59.00
Dims: 0.4 x 0.2 x 0.2" (1.0 x 0.6 x 0.5 cm)
Wt: 1 g
Vest-Agder, Norway
This tiny thumbnail piece consists of a misshapen chunk of yttrium-rich Aeschynite. The piece shows rather heavy damage and though some crystal form is visible, it is incomplete and missing its termination. It has a rusty-brown color and dull luster on its undamaged surfaces, but its freshly-damaged surfaces show a nearly black color and a brighter, pearly-to-vitreous luster. There is no host rock present, and it is protected within a small plastic box.
no photo
aes-1 ($ 59.00)
Vest-Agder, Norway
AESCHYNITE specimen aes-3
$ 37.00
Dims: 0.99x0.46x0.28" (2.51x1.18x0.72cm)
Wt: 31.0 ct (6.20g)
Hittere, Norway
This thumbnail specimen of aeschynite consists of a single tabular crystal with a roof termination. The ends are quite different (one brown and dull, the other more black and vitreous, likely due to a thin coating of calcite. The crystal has a large crack nearly penetrating the entire length, and indicates to me that the edges are also fractures. The crystal is predominately brown, although it is vertically striated both in texture and veins of black.
no photo
aes-3 ($ 37.00)
Hittere, Norway
AESCHYNITE specimen aes-4
$ 45.00
Dims: 2.21x1.52x0.54" (5.61x3.85x1.38cm)
Wt: 2.26oz (64.0g)
Hittero, Norway
This is a specimen of massive aeschynite-(Y) from its type locality, Hittero, Norway. It is relatively dense, black, opaque, and shows no crystal forms. It is acompanied by several other minerals, most notably a yellowish coating likely due to weathering, several areas of quartz crystals, at least one tiny spray of a blue mineral that looks like chrysocola, and a small patch showing metallic glints that looks like a metal sulfide (which is unlikely when associated with an oxide such as aeschenite).
no photo
aes-4 ($ 45.00)
Hittero, Norway


Copyright ©1995-2023 by Amethyst Galleries, Inc.