When people think of knits, they think of wool sweater, or cotton knit athletic wear. But much like any fiber can be woven, any fiber can be knit, including silk. Silk knits range from very fine, single filament knits, to four or more ply strands available for home knitting. Well, technically I guess you COULD knit at home with filament thread. But even a rank novice knitter like myself knows that it would take a devilish amount of thread to knit a sweater from filament.
Silk knit fabric is usually listed as Silk Jersey, so if you want to buy a silk knit, jersey is the best Google search term. For Silk Yarn for knitting at home, many yarn shops will have this in stock. Again, rank novice knitter here, but make sure the yard you purchase will work for the pattern you intend to knit.
As for sewing with silk knits…it can be devilishly hard. Silk is already a very slippery fiber in general. Knits are ALSO very slippery by nature. But, this fabric is particularly luscious, clinging to curves, gathers beautifully, and the drape is pure sophistication. On the flip side, knits in general are prone to shrinking. A lot. So either buy extra and make sure you pre-shrink before cutting, or determine ahead to dry-clean only the finished product.
Now, as for styles, like any knit, Silk Jersey is excellent for clinging styles and close fitting garments. Also like any knit, Silk Jersey is not good for structured garments.