Verdelite Identification Guide
How to identify Verdelite, the green gem variety of elbaite tourmaline, in the field and tell it from emerald, peridot and green glass.
Read the full Verdelite encyclopedia entry →
What Verdelite Looks Like
Verdelite is the traditional gem name for green elbaite tourmaline, ranging from yellowish and grassy green to deep bluish forest green.
- Color: all shades of green; commonly shows pleochroism (a darker green down the c-axis).
- Luster: vitreous (glassy).
- Transparency: transparent to translucent.
- Crystal habit: elongated, three-sided (trigonal) prisms with a rounded triangular cross-section and strong vertical striations parallel to the long axis, a signature of tourmaline.
Step-by-Step Field Checklist
- Look at the cross-section. A rounded triangular outline is a strong tourmaline indicator.
- Find the striations. Lengthwise grooves on prism faces are diagnostic.
- Check pleochroism. Rotate a transparent stone; green tourmaline darkens noticeably along the long axis.
- Test hardness. It scratches glass easily (Mohs 7-7.5) and resists a steel file.
- Look for color zoning. Green elbaite often grades to pink or colorless, hinting at the tourmaline family.
Key Diagnostic Tests
- Mohs hardness: 7-7.5.
- Streak: white/colorless.
- Cleavage: essentially none (poor); fracture uneven to conchoidal.
- Density: ~3.0-3.1 g/cm3.
- Pyroelectric/piezoelectric: tourmaline attracts dust or ash when warmed or rubbed, a classic confirming test.
- No acid reaction.
Common Look-Alikes
- Emerald (green beryl): hexagonal (six-sided) crystals, weaker pleochroism, often with three-phase inclusions; distinguished mainly by crystal form (hexagonal vs trigonal) and lack of strong striations.
- Peridot: olive/yellow-green only, lower hardness (6.5-7), strong doubling of back facets from high birefringence, and an oily luster.
- Green diopside/chrome diopside: has good cleavage (tourmaline does not) and lower hardness (~5.5-6.5).
- Green glass: shows gas bubbles, no pleochroism, no striations.
- Green sapphire: much harder (Mohs 9) and denser.
Where It Is Found
Verdelite occurs in granite pegmatites. Major sources include Brazil (Minas Gerais), Afghanistan, Pakistan, Nigeria, Madagascar, Mozambique, and Maine and California in the USA.
Frequently asked questions
Is Verdelite the same as green tourmaline?
Yes. Verdelite is the historic gem-trade name for the green variety of elbaite tourmaline.
How can you tell Verdelite from emerald?
Tourmaline forms three-sided (trigonal) striated prisms with strong pleochroism, while emerald is six-sided (hexagonal) beryl with weaker pleochroism and typical jardin inclusions.
What hardness is Verdelite?
About 7 to 7.5 on the Mohs scale, so it scratches glass easily and resists a steel knife.
Does Verdelite have cleavage?
No, tourmaline has essentially no cleavage; it breaks with an uneven to conchoidal fracture, which helps separate it from cleaving green minerals like diopside.
Verdelite identified by the community
Recent Verdelite specimens identified with Rock Identifier.
