Hydrogrossularite
Hydrogrossularite is a material that has long been mistakenly circulated as "jade." Because it contains hydroxyl groups (-OH) in its composition, it is considered a subspecies of grossular (a type of garnet). It does not form visible crystals to the naked eye and is characterized by being found in translucent to opaque massive forms. It tends to be green due to the inclusion of Cr (chromium) and pink due to Mn (manganese).
Characterized by its "jade-like" texture and translucent to opaque massive occurrence.
Basic Information
| English Name | Hydrogrossularite |
|---|---|
| Japanese Name | Kasui Zakuroishi |
| Chemical Composition | Ca3Al2[SiO4]3(OH)4 |
| Crystal System | Isometric |
| Hardness | 7 |
| Specific Gravity | Approx. 3.48 |
| Transparency | Translucent to Opaque |
Characteristics & Variations
- Visual Trends: Rather than forming transparent crystals, it occurs as dense masses, and some specimens have a soft texture that gives them a "jade-like" appearance.
- Color Factors: It tends to turn green with the inclusion of Cr (chromium) and pink with the inclusion of Mn (manganese).
- Potential for Misidentification: Having been treated as "jade" for a long time, caution is required regarding misidentification based on trade names.
Varieties
- Bicolor Garnet: Mixed with idocrase (vesuvianite), resulting from compositional changes. The boundary between the pink and yellowish-green colors is not clearly defined and transitions indistinctly.
Origin, Trade Names, Treatments & Simulants
Caution: Even when a trade name includes "jade," it is not the same as Jadeite or Nephrite. Furthermore, because it may be subjected to dyeing treatments, it is safest to verify the treatment information alongside the actual identity of the material rather than judging it by name alone during sourcing and appraisal.