Stone Types and Specifications

Thank you for your interest in our stone
Chrysoprase Mines of Australia produces four main stone types from our operations at Yerilla in Western Australia. These materials are produced both as individual stone types and in a variety of combinations with each other. Our primary product is Chrysoprase. We also produce Chalcedony, chert and Maganesite. Details and specifications follow:
  1. Chrysoprase
  2. Chalcedony
  3. Chert (Jasper)
  4. Siliceous Nickeliferous Magnesium Carbonates ("Magnesite")

Chrysoprase

Stone Types Index
Chrysoprase is naturally occurring microcrystalline quartz.

Colour: Green
Chemical Composition: Chrysoprase consists primarily of quartz (silicon dioxide or SiO2). The primary colouring agents are various compounds of nickel.
Moh's Hardness: 6.5 - 7.0
Specific Gravity: 2.58 - 2.64
Transparency: Transparent to translucent to opaque
Refractive Index: 1.530 - 1.539

Chalcedony

Stone Types Index
Chalcedony is naturally occurring microcrystalline quartz. The chalcedony family of rocks includes chrysoprase, gem chrysocolla chalcedony, agate, moss agate, onyx, cornelian and sard.

Colour: White to grey, available with dendrites or plain
Chemical Composition: Chalcedony consists primarily of quartz (silicon dioxide or SiO2).
Moh's Hardness: 6.5 - 7.0
Specific Gravity: 2.58 - 2.64
Transparency: Translucent to opaque
Refractive Index: 1.530 - 1.539

Chert (Jasper)

Stone Types Index
Chert is naturally occurring microcrystalline quartz. The name is used to describe many different stone types. Jasper is the red variety of chert.

Colour: Red - Brown.
Chemical Composition: Chert consists primarily of quartz (silicon dioxide or SiO2). The primary colouring agents are iron oxides, manganese, various carbonates and clay compounds.
Moh's Hardness: 6.5 - 7.0
Specific Gravity: 2.58 - 2.91
Transparency: Opaque
Refractive Index: 1.54

Siliceous Nickeliferous Magnesium Carbonates
("Magnesite ")

Stone Types Index
We produce a wide range of materials from the siliceous nickeliferous magnesium carbonate family of stone types. These go by a variety of trade names including Nickelian Magnesite, Citron, Lime Prase, and Lemon Chrysoprase. Gaspeite is a member of this family.

Colour: White - Yellow - Green. Available with dendrites or plain
Chemical Composition: Magnesite consists primarily of magnesium carbonate (MgCO2). Depending upon the level of silicification, quartz (silicon dioxide or SiO2) will be present in varying amounts. Colouring is due to the presence of high levels of nickel (assays recorded show 5.0% to 10.8% nickel respectively in yellow and green coloured stones).
Moh's Hardness: 3.5 - 4.0
Specific Gravity: 3.0 - 3.12
Transparency: Opaque
Refractive Index: 1.515 - 1.717