Helidore (Beryl)

Color: yellow, yellow/green
Moh’s Hardness: 7.5-8
Refractive Index: 1.57-1.60
Critical Angle: 39.97°
Specific Gravity: 2.65-2.75
Cleavage: None
Fracture: Conchoidal, tough
Dispersion: Medium (.014)
Heat Sensitivity: Slightly
Dichroism: weak (gold-yellow to greenish-yellow)
Birefringence (double refraction): Weak (.006-.009)
Crystal Structure: Hexagonal

Treatments: Often heat treated and irradiated...

What I prefer to polishing with: Cerium oxide with a Spectra Ultralap.

Jeff's Comments: Cuts and polishes like any other Beryl, usually no problems... I like to use a 1200 Nu Bond lap for pre-polish, it makes the polishing stage faster and easier. Orientating on the "c" is slightly better. Watch for silk and lilly pad type of inclusions perpendicular to the "c" axis.

Design Notes: About any design will work well... I prefer a deeper design and often cut Barions...

Design Links:
Aqua Cisor - This is great for clear rough if you have a piece that will work...
Blue Ice - Designed for very long crystals

Rough Links:
Beryl - Index of Beryl Rough
Aquamarine - Zambian
Aquamarine2 - Afghanistan crystals and huge pieces
Aquamarine3 - Seafoam and Blue Aquamarine from Nigeria.
Aquamarine4 - Large natural Mozambique crystals
Aquamarine5 - Nigerian Aquamarine
Collector Beryl (unusual colors)
Emerald - Zambian green Beryl
Goshenite (clear Beryl)
Helidore - Afghanistan yellow/green Beryl
Helidore 2 - Brazil yellow/green Beryl
Morganite - Pink Beryl, Peach/Pink Beryl
Beryl Parcels - Various parcels

Bargain Links:
Beryl Bargains

Return to Beryl Information Index

E-mail to inquire or order: jeff@faceters.com