How To Separate Frequently Encountered Pink Stones

- Visual observation: (10x lens) Look for color, luster, cut, doublet/triplet junctions, if any.

- Determine optic character: Single refractive (SR) / Double refractive (DR) / Anomalous Double refractive (ADR) / Aggregate (AGG).

- Spectrum: Many pink stones may have diagnostic spectrum.

- Microscope: Inclusions may be diagnostic, but look for inclusions that differentiate natural and synthetic, doublet / triplet.

- Dichroscope: Different cutting orientations of natural and synthetic corundum may be revealed by dichroscope.

- Fluorescence: Look under shortwave and longwave for diagnostic colors.

- Immersion cell: Use immersion cell and high refractive index liquid to separate doublets/triplets.

- Refractometer: Confirm spectroscope reading with refractometer.

The pink stones, which may resemble one another in appearance and values, are:

Scapolite (group)

- Hardness: 6
- Specific gravity: 2.50 – 2.71
- Refractive index: 1.54 – 1.58
- Optic sign: Uniaxial negative
- Birefringence: DR; 0.009/26
- Other points: Inclusions, color, R.I

Pink Beryl

- Hardness: 7.5
- Specific gravity: 2.80 (average)
- Refractive index: 1.57 – 1.58
- Optic sign: Uniaxial negative
- Birefringence: DR; 0.006
- Other points: Inclusions, color. Pink beryl may be treated. Pink beryl may look like Kunzite or glass. Gem quality stones are relatively clean. Analytical techniques may be required to detect treatments.

Tourmaline

- Hardness: 7
- Specific gravity: 3.03
- Refractive index: 1.62 – 1.64
- Optic sign: Uniaxial negative
- Birefringence: DR; 0.018
- Other points: Inclusions, color, luster. Tourmalines may be treated. Pink tourmaline may look like pink sapphire, pink spinel, pink beryl or glass. Gem quality stones are relatively clean. Analytical techniques may be required to detect treatments.

Pink Andalusite

- Hardness: 7.5
- Specific gravity: 3.18
- Refractive index: 1.63 – 1.64
- Optic sign: Biaxial negative
- Birefringence: DR; 0.010
- Other points: Color, pleochroism, luster.

Topaz

- Hardness: 8
- Specific gravity: 3.53
- Refractive index: 1.63 – 1.64
- Optic sign: Biaxial positive
- Birefringence: DR; 0.008
- Other points: Color, luster. Topaz may be treated. Pink topaz may look like pink sapphire, pink spinel, pink beryl or glass. Gem quality stones are relatively clean. Analytical techniques may be required to detect treatments.

Kunzite

- Hardness: 6.5
- Specific gravity: 3.18
- Refractive index: 1.66 – 1.68
- Optic sign: Biaxial positive
- Birefringence: DR; 0.015
- Other points: Pleochroism, cleavage, inclusions, color (may fade). Kunzite may be treated. Kunzite may look like pink beryl (morganite) or glass. Gem quality stones are relatively clean. Analytical techniques may be required to detect treatments.

Spinel

- Hardness: 8
- Specific gravity: 3.60
- Refractive index: 1.718
- Optic sign: SR
- Birefringence: -
- Other points: Color, spectrum, inclusions. Pink spinel may look like pink sapphire, pink tourmaline, kunzite, pink beryl or glass.

Taaffeite

- Hardness: 8
- Specific gravity: 3.60
- Refractive index: 1.717 – 1.723
- Optic sign: Uniaxial negative
- Birefringence: DR; 0.004
- Other points: Rare, color (usually blue purple).

Garnet (rhodolite)

- Hardness: 7.5
- Specific gravity: 3.78 (average)
- Refractive index: 1.75 (average)
- Optic sign: SR/ADR
- Birefringence: -
- Other points: Color, spectrum. Rhodolite may look like pink to purplish red sapphire, pink to purplish red spinel or glass.

Pink Sapphire

- Hardness: 9
- Specific gravity: 4
- Refractive index: 1.76 – 1.77 (average)
- Optic sign: Uniaxial negative
- Birefringence: DR; 0.008
- Other points: Color, inclusions (use microscope to separate natural vs synthetic), fluorescence. Pink sapphire may be treated. Pink sapphire may look like pink tourmaline, pink spinel, kunzite, pink beryl or glass. Gem quality stones are relatively clean. Analytical techniques may be required to detect treatment.

Synthetic sapphire

- Hardness: 9
- Specific gravity: 4
- Refractive index: 1.76 – 1.77 (average)
- Optic sign: Uniaxial negative
- Birefringence: DR; 0.008
- Other points: Color, inclusions (use microscope to distinguish flux and hydrothermal).

Synthetic cubic zirconia

- Hardness: 8.5
- Specific gravity: 5.65 +
- Refractive index: 2.15 +
- Optic sign: SR
- Birefringence: -
- Other points: negative refractive index, luster, color, orange flash on the pavilion, dispersion.

Diamond

- Hardness: 10
- Specific gravity: 3.52
- Refractive index: 2.42
- Optic sign: SR/ADR
- Birefringence: -
- Other points: negative refractive index, color, luster, inclusions, spectrum. Pink diamond is quite rare and expensive.

Glass

- Hardness: 5.5
- Specific gravity: 3.70
- Refractive index: 1.60-1.66
- Optic sign: SR/ADR
- Birefringence: -
- Other points: Soft, color, inclusions (gas bubbles), luster, spectrum