Wheal Rose (Wheal Lomax), Porthleven, Cornwall, England, UKi

Regional Level Types
Wheal Rose (Wheal Lomax)	Mine (Abandoned)
Porthleven	Civil Parish
Cornwall	County
England	Constituent Country
UK	Country

Colour: colourless, white, slightly brownish

Description: Not confirmed by analysis

Habit: tabular parallel to b(010), twinned on m(110), and showing the forms b(010), m(110), i(021), p(111); acicular; rarely bipyramidal crystals, combinations of p(111) with i(021) and m(110), showing polysynthetic growths and measuring up to 1 1/2 cm. along the vertical axis.

Description: Not confirmed by analysis

Habit: bladed.

Colour: colourless

Description: Russell and Hutchinson (1927): "The crystals of laurionite are colourless and translucent and bladed in form, attaining a length of 4 mm.[...] The following forms are present: b(010), m(110), n(120), d(012), and the prominent but somewhat doubtful form p(141). [...] The faces as a whole appeared to be etched and afford multiple images, with the exception of m(110) which gives good reflections. As in the case of the Laurion crystals the faces of b(010) are striated parallel to their intersection with the pyramid p(141), the latter being possibly a vicinal form as suggested by Dr. Herbert Smith. The edges formed by the intersection of the faces p(141) are always more or less curved, thus giving rise to the bladed form. No interference-figure can be seen looking through (010). The crystals when powdered are partially soluble in boiling water. The presence of lead and chlorine was determined. Of the three associated minerals, laurionite, phosgenite, and anglesite, the laurionite appears to have been the last formed, and partially invests the other two."

Habit: mamillary; lenticular (pseudomorphous after siderite)

Colour: velvety black; brown

Habit: The crystals are long narrow thin plates without for the most part any terminal faces and when measured gave angles consistent with the supposition that they are crystals of paralaurionite elongated along the symmetry-axis and twinned about a(100) with the faces of a large and those of c(001) small. [...] There is an excellent cleavage parallel to c(001). Indications of other faces in the zone a c were observed, and it is probable that h(201) is present on some crystals as a very narrow face. The important face m(110) mentioned by Herbert Smith was not observed, but a face making an angle of 24°24' with a was found instead. Simple indices cannot be assigned to this face ((510) would correspond to an angle from a of 25°38') and it is probable that it is an accidental face produced where one crystal has come in contact with another.[...]

Habit: The forms present are c(001), a(100), m(110), l(320), u(210), o(201), x (111), s(211).

Habit: hexagonal prisms, often partly hollow or slightly barrel-shaped.

Colour: bright grass-green to greenish-yellow

Habit: saccharoidal; pyramidal

Colour: deep brown