Mineral chemical class
Mineral chemical class — the 11 controlled values used across 433 bead material entries. Each value that has its own page lists every entry that carries it.
What this axis answers
This axis records which anion-based mineral class a material belongs to: silicates, carbonates, phosphates, sulfates, halides, oxides and hydroxides, sulfides and sulfosalts, native elements. Two further values catch what no single class fits: mixed or composition-dependent for rocks and polymineral aggregates, and not applicable where the material is no mineral at all. Each value follows the material family a term is filed under; it is not a composition test on an individual item.
How it differs from the other four axes
Origin class settles natural versus man-made; material domain settles inorganic, organic and manufactured; identity level settles which naming tier a term sits at; construction or treatment status settles synthesis and treatment. None of those is read off composition. Pearl shows the division: not applicable here, while domain calls it natural organic and biogenic. The blank marks a scope limit, not a gap in the data.
Two common misreadings
Malachite Agate leads with the name of a carbonate, yet the term is filed under quartz and chalcedony materials, so this axis reads it as a silicate. What is actually sold under it may be green chalcedony, dyed material or a copper-mineral aggregate, and only testing settles which; if the identification changes, the value on this axis no longer holds. Opal is hydrated amorphous silica but takes not applicable rather than any mineral class, because it is not a mineral species.
What it means for disclosure
Composition never enters the name. Clause 5.1.1 b) of GB/T 16552-2017 lets a mineral, rock or materials-science name that its Annex A does not list serve directly as the gem name, and clause 4.2.4.1 of the CIBJO Gemstone Book requires stones outside Annex 8 to be described by an IMA-recognised mineralogical name or a geological name only. A chemical class is a browsing label and does not go on a listing.
Controlled values on this axis
This table scrolls sideways on narrow screens.
| Value | Definition | Entries | Status |
|---|---|---|---|
| Silicates | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 205 | Has its own page |
| Carbonates | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 10 | Has its own page |
| Phosphates | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 9 | Has its own page |
| Sulfates | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 4 | Has its own page |
| Halides | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 2 | Fewer than three member entries; folded into the axis index page instead of a standalone page, to avoid thin content. |
| Oxides / hydroxides | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 34 | Has its own page |
| Sulfides / sulfosalts | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 2 | Fewer than three member entries; folded into the axis index page instead of a standalone page, to avoid thin content. |
| Mixed / composition-dependent | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 78 | A placeholder value rather than a real class (unknown / not applicable / mixed), so it has no page of its own; on entry pages the value is shown as plain text without a link. |
| Not applicable | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 82 | A placeholder value rather than a real class (unknown / not applicable / mixed), so it has no page of its own; on entry pages the value is shown as plain text without a link. |
| Native elements | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 4 | Fewer than three member entries; folded into the axis index page instead of a standalone page, to avoid thin content. |
| Borates and tungstates | Applies only to minerals or mineral-dominated materials; other materials use not applicable or composition-dependent. | 3 | Has its own page |