Spodumene Gemstones – Properties, Origins, Treatments and Buying Guide

Spodumene (Hiddenite) is one of the most elegant green gemstones, prized for its vivid, saturated colour and high clarity. Unlike softer stones that rely on delicate hues, Hiddenite displays an intense lime-to-emerald green glow that is highly collectible and ideal for fine jewellery.

In this guide we examine Spodumene (Hiddenite) from a professional gemmological and commercial perspective, covering its physical properties, crystal structure, treatments, origins and how to identify fine-quality stones.

Hiddenite is the green gem-quality variety of the mineral spodumene. Its vibrant green colour is caused by trace amounts of chromium within the crystal structure. Hiddenite typically forms long prismatic crystals in pegmatite veins and is highly valued for its transparency and brilliance. The gem is rarer than kunzite, the pink-to-lilac variety of spodumene.

Spodumene (Hiddenite) has the chemical formula:

LiAl(SiO₃)₂

This means it is composed primarily of:

Lithium
Aluminium
Silicon
Oxygen
Trace chromium (colouring element)

The chromium content gives Hiddenite its signature green colour, which ranges from pale lime to deep emerald green depending on concentration.

Hiddenite belongs to the pyroxene mineral group, a family of silicate minerals.

Its crystal system is monoclinic, forming long prismatic crystals that enhance its brilliance and make it highly desirable for faceting.

Hiddenite combines exceptional transparency, vivid green colour, and strong pleochroism (colour changes when viewed from different angles), making it one of the most visually captivating gemstones in its category.

Lustre
Vitreous, providing a bright, glass-like shine.

Transparency
Transparent with very few inclusions; the finest stones are eye-clean.

Refractive index
1.660 – 1.676, providing strong brilliance and sharp reflections.

Specific gravity
3.10 – 3.23, typical of spodumene gemstones.

Hiddenite occurs in shades of green:

Pale lime green
Vivid emerald green
Yellowish-green

High-quality Hiddenite shows strong saturation without dark tones.

Hiddenite has a Mohs hardness of 6.5–7, making it suitable for rings, pendants, and earrings when properly protected.

It has good toughness but may cleave if struck sharply along crystal planes.

Most Hiddenite is untreated. Rarely, gentle heat may be applied to enhance green colour or reduce brownish tones. Coatings or fracture fillings are uncommon and generally not used in fine-quality stones.

Avoid ultrasonic cleaners and harsh chemicals.
Use warm water, mild soap, and a soft brush.
Store Hiddenite separately from harder gemstones to prevent scratches and damage.

Major sources of Hiddenite include:

USA (North Carolina)
Brazil
Afghanistan
Madagascar