RE1‑B01
Muscovite.

The main ore mineral is muscovite, with a content of about 25%; the associated ore mineral is beryl, with a content of 3%–5%; the gangue minerals include plagioclase, quartz, etc., totalling about 70%.

Muscovite belongs to the monoclinic system and occurs as flaky crystals. It is pale grey, with a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {001} is perfect, while {110} and {010} are imperfect. Thin flakes are elastic. Its hardness is 2–3 on the (001) face and 4 perpendicular to (001). Its density ranges from 2.76 to 3.10 g/cm³. It has excellent insulating properties and is insoluble in acids.

RE1‑B02
Muscovite.

The ore consists entirely of muscovite. It belongs to the monoclinic system and occurs as flaky crystals. It is pale green in colour, with a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {001} is perfect, while {110} and {010} are imperfect. Thin flakes are elastic. Its hardness is 2–3 on the (001) face and 4 perpendicular to (001). Its density ranges from 2.76 to 3.10 g/cm³. It has excellent insulating properties and is insoluble in acids.

The specimen is produced in the muscovite‑quartz zone of the No. 3 pegmatite vein at Keketuohai.

RE1‑B03
Muscovite.

The ore consists entirely of muscovite. It belongs to the monoclinic system and occurs as flaky crystals. It is greyish‑white in colour, with a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {001} is perfect, while {110} and {010} are imperfect. Thin flakes are elastic. Its hardness is 2–3 on the (001) face and 4 perpendicular to (001). Its density ranges from 2.76 to 3.10 g/cm³. It has excellent insulating properties and is insoluble in acids.

RE1‑B04
Tourmaline (tourmaline single crystal).

The tourmaline is black in colour, with a vitreous lustre and a hardness greater than that of a knife. It belongs to the trigonal system and exhibits a high degree of euhedralism. The crystals occur as trigonal prisms, with prism heights up to 9 cm and prism face widths of 6 cm; the three prism faces are equal in width. At both the top and bottom ends of the prism, three triangular faces are developed, intersecting at angles of 120° each. Vertical striations are well developed on the prism faces.

RE1‑B05
Albite‑tourmaline‑quartz pegmatite.

The rock is brownish‑grey with a slight purplish tint, with a microcrystalline texture and a massive structure. The main mineral is quartz, followed by tourmaline and albite, with minor muscovite.

• Quartz: Colourless, transparent to brownish‑grey, translucent, with a greasy lustre and a hardness greater than that of a knife. It is poorly crystallised and occurs as massive aggregates, accounting for about 70% of the rock.
• Tourmaline: Rose‑red in colour, with a vitreous lustre and a hardness greater than that of a knife. It belongs to the trigonal system and exhibits a long prismatic crystal form, with prism heights of 2–3 cm and prism face widths of 1–10 mm. Vertical striations are well developed on the prism faces. This tourmaline is probably elbaite (lithium tourmaline), and accounts for about 20%.
• Albite: Milky‑white to pale egg‑shell blue, with a vitreous lustre and a hardness greater than that of a knife. It occurs as tabular‑platy crystals, with crystal sizes of 2 cm × 5 cm and a thickness of 1–2 mm, constituting about 5%.
• Muscovite: White, with a pearly lustre and low hardness. It occurs as flakes with diameters of 1–5 mm, mostly distributed along the margins of the elbaite crystals or in the interstices between albite grains, with a content of less than 1%.

RE1‑B06
Albite‑tourmaline‑quartz pegmatite.

The rock is pale greyish‑white to green in colour, with a pegmatitic texture and a massive structure. The main mineral is quartz, followed by tourmaline, with minor muscovite.

• Quartz: Colourless to milky‑white, transparent to translucent, with a greasy lustre and a hardness greater than that of a knife. It occurs as massive aggregates with poor crystallinity, accounting for about 60% of the rock.
• Tourmaline: Green to dark ink‑green, with a vitreous lustre, hardness greater than that of a knife, and uneven fracture. The crystals are trigonal or hexagonal prisms, with crystal lengths up to 2–3 cm, though well‑formed crystals are rare. Some occur as prismatic granular aggregates. Vertical striations are well developed on the prism faces. This tourmaline is of the elbaite (lithium) variety, and constitutes about 20%.
• Muscovite: The aggregates are white, while individual flakes are colourless and transparent, with a vitreous to pearly lustre and a hardness lower than that of a knife. It shows good euhedralism, occurring as large aggregate masses, with individual flakes up to 2 cm × 3 cm in diameter and aggregate thicknesses up to 2 cm. It is distributed as large patchy masses within the quartz, accounting for about 20%, and is closely associated with the tourmaline.

RE1‑B07
Feldspar‑mica‑elbaite pegmatite.

The rock is yellowish‑white, pink, and pale green in a mottled pattern, with a pegmatitic texture and a massive structure. The main minerals are feldspar, tourmaline, quartz, and minor muscovite.

• Feldspar is cleavelandite (leafy albite), pale greenish‑grey to pale egg‑shell blue, with a vitreous lustre, translucent, and occurs as euhedral to subhedral tabular‑platy crystals. The crystals are 0.2–1 mm thick, up to 2–3 cm in length, and 1–2 mm in plate thickness, accounting for about 10%.
• Tourmaline is dark green to pale green to rose‑red to light pink, with a vitreous lustre and a hardness greater than that of a knife. It occurs as euhedral to subhedral hexagonal prismatic crystals, with prism heights exceeding 2 cm and prism diameters up to 2 cm. The prism faces show curved arc‑shaped characteristics and are well developed with vertical striations. In the same crystal, the outer margin is dark green, gradually changing inward to pale green, while the centre is pink to rose‑red, forming a “green rim with a red core”. The green rims vary in thickness and extent: sometimes they are 1–2 mm thick, sometimes absent, and sometimes the green dominates with only a small pink core. Fractures are uneven. The tourmaline content is about 40%.
• Quartz is colourless, transparent, with a greasy lustre and a hardness greater than that of a knife, accounting for about 5%.
• Muscovite is white, colourless and transparent, euhedral to subhedral granular and flaky, with grain sizes of 2–5 mm and flake diameters around 5 mm. It occurs as large patchy masses in the interstices between elbaite crystals, with a content of about 25%.

RE1‑B08
Tourmaline‑bearing pegmatite.

Pegmatitic texture, massive structure. The main minerals are feldspar, tourmaline, quartz, and minor muscovite. The elbaite (lithium tourmaline) content is relatively low, about 15%.

The colour distribution of the elbaite shows green rims (haloes) on the margins, with rose‑red cores in the centre. In addition, some crystals have a rose‑red crust (halo) with a pale bluish‑green core, as well as single‑coloured green or rose‑red tourmaline.

Muscovite and quartz aggregates are relatively fine‑grained, accounting for about 50%. Cleavelandite (leafy albite) content is about 20%, and microcline content is 10%–15%.

RE1‑B09
Tourmaline‑spodumene‑muscovite‑albite pegmatite.

The rock is greyish‑white to pale egg‑shell blue in colour, with a pegmatitic texture and a massive structure. The main mineral is cleavelandite (leafy albite), with minor quartz, muscovite, tourmaline, and spodumene.

• Cleavelandite (leafy albite): Pale greyish‑white to pale egg‑shell blue, with a vitreous lustre and a hardness greater than that of a knife. The crystals are commonly tabular‑platy and show low euhedralism; well‑formed crystals are not observed. It accounts for about 80% of the rock.
• Muscovite: White, colourless and transparent, with a vitreous lustre and a hardness lower than that of a knife. It is easily peeled into flakes, with flake diameters generally 1–2 cm, constituting about 5%.
• Elbaite (lithium tourmaline): Rose‑red in colour, with prismatic crystals, well‑developed vertical striations on prism faces, a vitreous lustre, and a hardness greater than that of a knife. Prism crystals can reach up to 5 cm in length, but show low euhedralism. Granular aggregates of elbaite are also present, closely associated with muscovite, accounting for about 5%.
• Spodumene: Yellowish‑white to pale flesh‑red, with a vitreous lustre and a hardness greater than that of a knife. It occurs as veinlets or patchy masses, in irregular tabular or granular forms, and is commonly associated with muscovite, constituting about 5%.

RE1‑B10
K‑feldspar‑cleavelandite‑muscovite‑quartz‑tourmaline pegmatite.

The rock is yellowish‑white to black in a mottled pattern, with a pegmatitic texture and a massive structure. The minerals composing the pegmatite are all coarse to microcrystalline K‑feldspar, cleavelandite, muscovite, quartz, and tourmaline.

• K‑feldspar: Yellowish‑white to pale flesh‑red, with a vitreous lustre and a hardness greater than that of a knife. Crystals are mostly prismatic or tabular. Prismatic crystals can reach up to 3 cm in diameter, but are largely replaced by cleavelandite; the K‑feldspar is commonly porous and cut by cleavelandite veinlets. Content is about 10%.
• Cleavelandite (leafy albite): Colourless to pale egg‑shell blue, with a vitreous lustre, transparent to translucent. It occurs as tabular‑platy crystals with good euhedralism, plates 1–2 mm thick, 1–2 cm wide, and 3–4 cm long. The crystals interpenetrate and intergrow, sometimes forming drusy aggregates with vugs between crystals. Content is about 50%.
• Muscovite: White, colourless and transparent, with a vitreous lustre, one set of perfect cleavage, hardness less than that of a knife. It occurs as euhedral large flaky or tabular aggregates, with maximum flake diameters up to 1 cm, unevenly distributed. Content is about 2%.
• Quartz: Greyish‑brown to smoky grey, with a greasy lustre, translucent, hardness greater than that of a knife. It occurs as coarse crystalline (2 cm × 5 cm) masses, generally about 1 cm in size, and in fairly euhedral hexagonal pyramidal‑prismatic forms. Content is about 3%.
• Schorl (black tourmaline): Black, with a vitreous lustre, hardness greater than that of a knife, and uneven fracture. It occurs as coarse crystalline masses; crystals longer than 5 cm can be seen, but well‑formed crystal faces are not observed. It is distributed as large patchy masses in the pegmatite, with a content of about 30%.

In the rock, cleavelandite can be seen cutting across schorl, indicating that albitisation post‑dates the tourmaline mineralisation stage.

RE1‑B11
Muscovite‑cleavelandite‑elbaite pegmatite.

The rock is milky‑white to pale egg‑shell blue and greyish‑green in colour, with a pegmatitic texture and a massive structure. The rock consists entirely of pegmatitic cleavelandite, tourmaline, and muscovite.

• Cleavelandite (leafy albite): Milky‑white to pale egg‑shell blue, with a vitreous lustre and a hardness greater than that of a knife. It occurs as tabular‑platy subhedral crystals, but well‑formed crystals are not observed. The aggregates are massive or lumpy, accounting for about 70%.
• Tourmaline: Greyish‑green to green, with a vitreous lustre and a hardness greater than that of a knife. It occurs as euhedral to subhedral prismatic and hexagonal prismatic crystals, generally 3 mm × 15 mm, with some slightly larger. Vertical striations are well developed on prism faces. Based on its colour, it is identified as elbaite (lithium tourmaline), and constitutes about 20%.
• Muscovite: White, colourless and transparent, with a vitreous lustre and a hardness less than that of a knife. It occurs as large flaky to tabular aggregates, easily peeled into thin flakes due to one set of perfect cleavage, accounting for about 10%.

The rock can be broadly divided into two parts: one part is composed almost entirely of cleavelandite, containing very little tourmaline and muscovite; the other part consists mainly of elbaite and muscovite, with minor cleavelandite. The elbaite and muscovite are closely intergrown, occurring as coarse pegmatitic interlocking crystals. This bimodal distribution results from pegmatite zoning.

RE1‑B12
Aquamarine.

Aquamarine belongs to the beryl group in mineralogy and is a silicate of beryllium and aluminium. The crystals belong to the hexagonal system and occur as hexagonal prisms. Due to the presence of Fe²⁺, the specimen exhibits a pale blue colour. It has one set of imperfect cleavage parallel to {0001}. It shows a vitreous lustre and is translucent. Its hardness is 7.5–8, and its density ranges from 2.6 to 2.9 g/cm³. The main ore mineral is beryl, with a content of 3%–5%. The gangue minerals are mainly quartz, with minor garnet, totalling about 95%.

RE1‑B13
Aquamarine.

Aquamarine belongs to the beryl group in mineralogy and is a silicate of beryllium and aluminium. The crystals belong to the hexagonal system and occur as hexagonal prisms. Due to the presence of Fe²⁺, the specimen exhibits a pale blue colour. It has one set of imperfect cleavage parallel to {0001}. It shows a vitreous lustre and is translucent. Its hardness is 7.5–8, and its density ranges from 2.6 to 2.9 g/cm³. The main ore mineral is beryl, with a content of about 10%. The gangue minerals are mainly feldspar, quartz, and muscovite, totalling about 90%.

RE1‑B14
Biotite.

The crystals belong to the monoclinic system, and the aggregates occur as flakes. Due to the high content of ferric iron, the specimen exhibits a dark greenish‑black colour. It has a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {001} is perfect. Thin flakes are elastic. Its hardness is 2–3, and its density ranges from 3.02 to 3.12 g/cm³. Its insulating properties are relatively poor. It is insoluble in acids.

RE1‑B15
Kyanite.

The crystals belong to the triclinic system, and the individuals occur as parallel‑faced prismatic crystals. They are pale yellow in colour, with a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {100} is perfect, {010} is moderate, and {001} is a parting. Hardness varies with direction: on (100), it is 4.5 parallel to the c‑axis and 6 perpendicular to the c‑axis; on (010) and (110) faces, it is 7 in the transverse direction. It is brittle. Density ranges from 3.53 to 3.65 g/cm³.

RE1‑B16
Kyanite.

The crystals belong to the triclinic system, and the individuals occur as parallel‑faced prismatic crystals, with aggregates showing a radial habit. They are pale blue in colour, with a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {100} is perfect, {010} is moderate, and {001} is a parting. Hardness varies with direction: on (100), it is 4.5 parallel to the c‑axis and 6 perpendicular to the c‑axis; on (010) and (110) faces, it is 7 in the transverse direction. It is brittle. Density ranges from 3.53 to 3.65 g/cm³.

RE1‑B17
Kyanite.

The main ore mineral is kyanite, with a content of about 40%. The gangue minerals are mainly feldspar, quartz, and biotite, totalling about 60%.

The crystals belong to the triclinic system, and the individuals occur as parallel‑faced prismatic crystals, with aggregates showing a radial habit. They are pale blue in colour, with a vitreous lustre and a pearly lustre on cleavage surfaces. Cleavage {100} is perfect, {010} is moderate, and {001} is a parting. Hardness varies with direction: on (100), it is 4.5 parallel to the c‑axis and 6 perpendicular to the c‑axis; on (010) and (110) faces, it is 7 in the transverse direction. It is brittle. Density ranges from 3.53 to 3.65 g/cm³.