Amethyst Oval cut loose faceted natural 4.3 cts 13x11x7mm O792

 We sell rough and cut gemstones, offering a wide range of rough gemstones for specimen-cabbing-facet and beautiful cut stones ready for your mount..Either for a new piece of jewelry or replacing a stone in an existing piece of jewelry.We offer thousands of lots, all with individual photos, what you see in the photo is what you will receive. Tommysrocks, an internet only business since 2002, giving our internet customers 100% of our attention.

CLARITY SCALE
IF VERY HIGH QUALITY & FREE FROM INCLUSIONS.
VVS HIGH QUALITY WITH VERY SLIGHT INCLUSIONS.
VVS1 HIGH QUALITY WITH SLIGHT  INCLUSION.
VS FINE QUALITY WITH  INCLUSION SLIGHTLY VISIBLE TO THE NAKED EYE.
VS1 FINE QUALITY WITH INCLUSION VISIBLE TO THE NAKED EYE.
SI GOOD QUALITY WITH  INCLUSIONS VISIBLE TO THE NAKED EYE.
SI1 INCLUSIONS BECOMING PROMINENT TO THE EYE.
I INCLUDED.

THIS GEMSTONE IS GRADED:  I F

Mohs hardness: 7

Refractive index: 1.544-1.553

Critical angle: 40°

Specific gravity: 2.63-2.65

Cleavage: None

Fracture: Conchoidal, brittle.

Dispersion: Medium (.013)

Heat sensitivity: Low

Pleochroism: Amethyst: very weak (purple to grayish purple); Natural citrine: weak (yellow to light-yellow); Prasiolite: very weak (light-green to paler green); Rock crystal: colorless, no dichroism; Rose quartz: weak (pink to paler pink); Natural dark smoky: definite (brown to reddish-brown).

Birefringence (double refraction): Weak (.009)

Crystal structure: Hexagonal

Treatments: Oro Verde, lemon citrine, smoketrine and most dark gray smoky quartz without any brown tones are all irradiated.  Citrines are often heat treated to improve color and give a reddish tint.  Most citrine is amethyst that has been heat treated.  Some smoky can be heated to create citrine.  Prasiolite is heat treated amethyst and citrine from one locality.