Main Difference
The main difference between Mica and Talc is that the Mica is a phyllosilicate minerals and Talc is a phyllosilicate mineral
Mica
The mica group of sheet silicate (phyllosilicate) minerals includes several closely related materials having nearly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition. The nearly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms.
The word mica is derived from the Latin word mica, meaning a crumb, and probably influenced by micare, to glitter.
Talc
Talc is a clay mineral composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often in combination with corn starch, is widely used as baby powder. This mineral is used as a thickening agent and lubricant, is an ingredient in ceramics, paint and roofing material, and is also one of the main ingredients in many cosmetic products. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage, uneven flat fracture and it is foliated with a two dimensional platy form.
The Mohs scale of mineral hardness is based on scratch hardness comparison, ranging from 1-10, a value of 10 being the hardest of minerals. Talc is the defining value 1 and therefore the softest of minerals. Any mineral below a value of 2 on Mohs scale of mineral hardness can be scratched by a fingernail. When scraped on a streak plate it produces a white streak, though this indicator is of little importance because most silicate minerals produce a white streak. Talc is translucent to opaque with colors ranging from whitish grey to green with a vitreous and pearly luster. Talc is not soluble in water, but is slightly soluble in dilute mineral acids.Soapstone is a metamorphic rock composed predominantly of talc.
Mica (noun)
Any of a group of hydrous aluminosilicate minerals characterized by highly perfect cleavage, so that they readily separate into very thin leaves, more or less elastic.
Talc (noun)
Originally a large range of transparent or glistening foliated minerals. Examples include mica, selenite and the hydrated magnesium silicate that the term talc generally has referred to in modern times (see below). Also an item made of such a mineral and depending for its function on the special nature of the mineral (see next). Mediaeval writers adopted the term from the Arabic.isbn=978-0-19-861271-1.
Talc (noun)
A microscope slide made of a plate of mica, generally in use from the start of modern microscopy until the early nineteenth century, after which glass slides became the standard medium.
Talc (noun)
A soft mineral, composed of hydrated magnesium silicate, that has a soapy feel and a greenish, whitish, or grayish color, and usually occurs in foliated masses.
Talc (noun)
Talcum powder.
Talc (verb)
To apply talc to.
Mica (noun)
a shiny silicate mineral with a layered structure, found as minute scales in granite and other rocks, or as crystals. It is used as a thermal or electrical insulator.