Feldspar materials
Feldspar-group minerals, their compositional varieties, and gem materials such as moonstone and sunstone; an optical-effect name does not denote a single mineral species.
What this family is
The name adularescence is applied loosely: classic moonstone is an orthoclase–albite intergrowth, yet labradorite, sanidine and others can also show it, so the actual mineral composition must be established by identification. Sunstone may be orthoclase or plagioclase, and labradorite denotes a plagioclase composition range and variety rather than an IMA-recognised species.
Orthoclase, microcline, albite and anorthite are the mineral species listed here.
Scope of this family
Feldspar-group minerals, their compositional varieties, and gem materials such as moonstone and sunstone; an optical-effect name does not denote a single mineral species.
Representative members (12)
The standard materials in this family: mineral species, varieties, rocks and other materials whose name identifies what they are. Trade names are listed separately below.
Common confusions
Names in this family that do not by themselves say what the material is, and man-made or assembled products recorded against its materials. Each line says what the item actually is.
Trade names in this family
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| Name | Type of name | What it actually is |
|---|---|---|
| Black Moonstone | Trade name: colour / appearance variety | A market name for dark feldspar sold for a moonstone-like effect; it has no unified mineralogical definition and cannot be assumed to be moonstone. |
| Perthite | Trade name: colour / appearance variety | A name for the striped intergrowth structure inside potassium feldspar, not a separate mineral species; names such as "green perthite" are common on the market. |
| Rainbow Moonstone | Trade name: cultural / brand designation | A commercial name for white Labradorite showing an iridescent sheen. It should not be labelled as orthoclase Moonstone; giving the Chinese and English names side by side with an explanation is recommended. |
| Spectrolite | Trade name: colour / appearance variety | A trade name for Labradorite with intense colour play, mostly associated with material from Finland. It is not a separate mineral species, and an origin should not be assumed from the name. |
| Sunstone | Trade name: colour / appearance variety | A feldspar gem name that describes appearance; it may be orthoclase or plagioclase. Its GB/T basic name is "Sunstone", and not all of it shows an aventurescence effect. |
Synthetic, assembled or treated counterparts
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| Name | Counterpart of | What it actually is |
|---|---|---|
| Albite Jade | Albite | A mineral aggregate used as jade, composed mainly of albite; its natural-jade basic name in Table A.2 of GB/T 16552-2017 is “albite jade”. |
Member entries (17)
Treatments recorded on member entries
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| Treatment | Member entries | Disclosure requirement |
|---|---|---|
| Filled / Fracture-filled | Albite, Amazonite, Andesine, Anorthite, Black Moonstone, Bytownite, Feldspar, Labradorite, Labradorite (Spectrolite), Microcline, Moonstone, Oligoclase, Orthoclase, Perthite, Rainbow Moonstone, Spectrolite, Sunstone | Name the filler (resin, oil, polymer, glass or lead glass) and bear in mind that fillings can be unstable and may deteriorate or change colour over time. LMHC Information Sheet #3 treats corundum with glass in two ways: glass in fissures or cavities is still reported on natural corundum as a filling, and only a badly fractured single piece infused throughout, or small fragments bound together with glass, is reported as a manufactured product. |
| Diffusion-treated | Albite, Amazonite, Andesine, Anorthite, Black Moonstone, Bytownite, Feldspar, Labradorite, Labradorite (Spectrolite), Microcline, Moonstone, Oligoclase, Orthoclase, Perthite, Rainbow Moonstone, Spectrolite, Sunstone | Must be disclosed. Surface diffusion produces colour only in a thin layer that repolishing can remove; bulk diffusion is permanent but still requires disclosure. |
| Irradiated | Albite, Amazonite, Andesine, Anorthite, Black Moonstone, Bytownite, Feldspar, Labradorite, Labradorite (Spectrolite), Microcline, Moonstone, Oligoclase, Orthoclase, Perthite, Rainbow Moonstone, Spectrolite, Sunstone | Must be disclosed. Stability under irradiation varies by material: irradiated blue topaz keeps a stable colour and irradiated smoky quartz or coloured diamond can, but in some materials the irradiated colour fades in light or heat; colour stability must be pointed out. |
| Coated | Albite, Amazonite, Andesine, Anorthite, Black Moonstone, Bytownite, Feldspar, Labradorite, Labradorite (Spectrolite), Microcline, Moonstone, Oligoclase, Orthoclase, Perthite, Rainbow Moonstone, Spectrolite, Sunstone | Must be disclosed. Coatings may be abraded, flake off or discolour, and coating is not a permanent enhancement; the coating material must be disclosed (e.g. Mystic Topaz is coated topaz), and the treated effect must not be implied to be natural. |
| Waxed | Amazonite | Must be disclosed. CIBJO's care annex counts wax among the treatments that are not permanent, so the matching care must also be passed on to the buyer: keep it away from solvents, household chemicals and heat. |
Care codes on member entries
Member entries cite these CIBJO special-care codes: special-care code a, special-care code b, special-care code j, special-care code k. General gem care gives the full wording of every code.
Where members are recorded
Some member entries record the localities where their materials are found; Recorded localities shows them on a sketch map and lists them by continent.
Names
- 简体中文
- 长石材料
- 繁體中文
- 長石材料
- English
- Feldspar materials
- 日本語
- 長石質材料
Authority source
- Authority source
- Review status
- Reviewed against CIBJO, GB/T and IMA boundaries.
Distribution across the other axes
All 17 members share these values:
- Origin class
- Natural materials
- Material domain
- Natural inorganic gem materials
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown