The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Refractive Index||1.653 - 1.682|
|Colors||Colorless yellow green blue violet gray|
|Fracture||Uneven to splintery|
|Hardness||6.5 - 7.5|
|Specific Gravity||3.00 - 3.21|
|Birefringence||.014 - .027|
|Cleavage||Perfect 2 directions|
|Stone Sizes||Kunzite to very large, Hiddenite usually under 2 carats|
|Enhancements||Irradiation produces pink from colorless or green from pink. Rare, colors fade when exposed to light.|
|Transparency||Transparent to Opaque|
|UV Long||Kunzite: moderate to strong, pink to orange. Hiddenite: inert. Yellow Green: moderate to strong, orange to yellow.|
|UV Short||Kunzite: weaker, pink to orange. Hiddenite: inert. Yellow Green: weaker orange to yellow.|
|Absorption Spectrum||Kunzite: not diagnostic. Hiddenite: double line at 6905/6860, weak lines at 6690, 6460, broad absorption at 6200. Yellow Green: strong band at 4375, weak band at 4330.|
|Identifying Characteristics||Hollow growth tubes|
|Pleochroism||Strong. Kunzite: colorless - pink or violet. Hiddenite: colorless - pale green/green or blue green.|
Spodumene is from the Greek word spodumenos which means burnt to ashes. This is a reference to its most common color. You will rarely find gray spodumene cut as gems, but the other colors can be spectacular.
Kunzite is the pink variety of spodumene. It is primarily from Afghanistan. Strongly pleochrotic, the crystals are colorless on the long axis and pink to violet down the C axis. The stronger the color, the higher the value, but large gems are available at moderate prices.
Yellow spodumene is found in Brazil and Afghanistan, with the strongest colors coming from the latter.
Blue, blue/green and green stones are found in a number of localities. The blue stones fade when exposed to light, so they are only suitable as collectors items.
Hiddenite is a medium dark green, darker than from other localities. It is only found in North Carolina, USA. The gems cut from it are rarely over two carats and is highly valued.
Spodumene has perfect cleavage in two directions, making it exceptionally difficult to cut. One also has to consider this when creating jewelry. The cleavage direction is right on the girdle, so great care needs to be taken when tightening prongs. (See Cutting Kunzite for more information.) Also consider how it will be worn. It only takes a little shock to split a stone on the cleavage.
- Kunzite pink to violet
- Hiddenite green
- Tripphane yellow