Calcite crystals occur in a wide variety of habits, the
scalenohedron and rhombohedron being the most common forms.
Crystal habits range from elongated hexagonal prisms with low-angle rhombohedron terminations to prism and
scalenohedron combinations in varying proportions.
It occurs in a wide variety of habits, but the
scalenohedron and rhombohedron are the most common forms.
According to Kostov (1968) and Moroshkin and Frishman (2001), the temperature of crystallization of various calcite forms proceeds from the {10[bar.1]1} rhombohedron at high temperature to the {[bar.1][bar.1]20} prism, {21[bar.3]1}
scalenohedron, and lastly the {02[bar.1]1} steep rhombohedron at low temperature.
Forms like the
scalenohedron can be generated by stacking tiny rhombohedrons in a certain way.
obtuse rhombohedron-- flattened III {h0-h1} obtuse rhombohedron colorless to white, locally coated "pseudocubic" with brown iridescent material IV {h0-h1} obtuse rhombohedron colorless V globular clusters white VI {hk-il} acute
scalenohedron colorless to white VII {hk-i1}, {h0-h1} obtuse colorless to white
scalenohedron modified by obtuse rhombohedron Quarries Where Type Crystal Forms Color (UV) Observed* I {h0-h1} obtuse rhombohedron yellow BG, PL "pseudocubic" II {h0-h1}, {0k-k1} pos.
Microsparite and sparite calcite crystals are mostly equant to elongated rhombohedrons or
scalenohedrons, but also a few prismatic crystals were observed.
The big calcite crystals are highly lustrous and limpidly colorless and transparent; some are fat
scalenohedrons while others are face-rich, complex, nearly equant forms of generally rhombohedral aspect.
It forms crusts of white opaque or colorless to yellow transparent
scalenohedrons and other crystal habits, usually less than 2 cm long and commonly exhibiting an orange fluorescence.
Calcite from the locality forms clean, pretty, compound "dogtooth" crystals composed of
scalenohedrons in parallel growth, pale orange and translucent and reaching 5 cm; matrix specimens reach 10 cm.
The manganese-tinted calcite in these pieces forms highly lustrous, translucent to transparent, very pale pinkish purple, twinned
scalenohedrons reaching 25 cm long.
They show hollow, pointed triangular shapes which very probably are molds after calcite
scalenohedrons. The molds are composed of tiny black sphalerite crystals mixed with larger galena crystals up to 5 mm, coated by tin-white arsenopyrite crystals on their inner surfaces.