Chrome Chalcedony Identification Guide

What Chrome Chalcedony Looks Like

Chrome chalcedony, also called mtorolite (from Mtoroshanga, Zimbabwe), is a microcrystalline quartz (chalcedony) colored a rich green by chromium. The color ranges from medium leek-green to deep emerald-green, usually even and saturated, sometimes with darker mottling or veining. It is translucent to nearly opaque with a waxy to glassy luster and a smooth, fine, homogeneous texture with no visible grains. It is often cut into cabochons and beads and resembles fine green jade.

Step-by-Step Field ID Checklist

1. Color: Confirm a vivid, even chromium-green, leek to emerald, without the yellowish cast of nickel-colored stones.
2. Texture: Look for a fine, dense, homogeneous body with no visible crystals.
3. Luster and transparency: Waxy to glassy; translucent on edges.
4. Hardness test: It scratches glass and steel (Mohs ~7).
5. Fracture: Conchoidal with sharp edges.
6. Acid test: No fizz (silica).

Key Diagnostic Tests

• Hardness: Mohs ~7; not scratched by a knife (separates it from softer green stones).
• Fracture: Conchoidal.
• Acid reaction: None.
• Density: ~2.6 g/cm³.
• Chelsea filter: Chromium-colored chrome chalcedony often shows a reddish/pink reaction, unlike nickel-colored chrysoprase, which stays green.

Common Look-Alikes and How to Tell Them Apart

• Chrysoprase: Also green chalcedony but colored by nickel, giving an apple- to yellow-green; chrome chalcedony is deeper/bluer green and tends to appear red under a Chelsea filter.
• Jadeite / nephrite jade: Jade has a more granular or fibrous tough texture; chrome chalcedony is uniform chalcedony with conchoidal fracture. Jadeite is similar in hardness, so use texture and color zoning.
• Green aventurine: Has glittery mica/fuchsite inclusions; chrome chalcedony is clean and even.
• Dyed green chalcedony: Color may concentrate in cracks; chrome chalcedony's color is natural and even, and shows the Chelsea-filter reaction.
• Maw-sit-sit / green serpentine: Softer or more mottled; chrome chalcedony is hard, uniform quartz.

Where Chrome Chalcedony Is Typically Found

Chrome chalcedony comes principally from Zimbabwe (Mtorolite, around Mtoroshanga) and is associated with chromium-bearing rocks. Similar chromium-colored green chalcedony has been reported from Turkey and other localities tied to chromite-rich ultramafic settings. Look for it in silica veins near chromite deposits and in the lapidary trade as polished green cabs.