Barite
BaSO₄ · Orthorhombic · also called baryte, barytes, desert rose
Barite is the mineral that teaches beginners to weigh a specimen in their hand. Nothing else that looks this ordinary is this dense — barium is a heavy element, and a barite specimen feels roughly twice as heavy as a calcite one of the same size.
Properties
- Mohs hardness
- 3–3.5
- Streak
- white
- Lustre
- vitreous, pearly
- Colour
- Usually white or pale; sand-included 'barite roses' are reddish brown.
- Cleavage
- Perfect in one direction and good in two more, producing blocky broken fragments.
- Fracture
- Uneven
- Specific gravity
- 4.3–4.6 (water = 1)
- Magnetism
- Not magnetic
- Acid test
- No reaction
- UV
- Some specimens fluoresce
Tests that confirm barite
- Remarkably heavy for a pale, non-metallic mineral — this is the diagnostic property, and it is obvious in the hand.
- Soft enough to scratch with a copper coin.
- Often forms flat tabular 'blades' stacked into rosettes.
What barite gets confused with
Each of these is settled by one test. Run that test first.
Heft. Barite is much heavier, and it does not fizz in acid.
Celestine
Celestine is slightly lighter and more often blue; the two need chemical tests to separate reliably.
Where it is found
Hydrothermal veins, and as concretions and rosettes in sandstone and desert soils.
Is it worth anything?
Inexpensive. Well-formed blue barite and intact desert roses have modest collector value.