Glass-ceramic compositions, articles, and methods of making the same

1 . A glass-ceramic composition comprising:

a) from about 5 mol % to about 7.5 mol % of Al 2 O 3 ;

b) from about 20 mol % to about 25 mol % of Li 2 O;

c) from about 48 mol % to about 80 mol % of SiO 2 ;

d) from 0 mol % to about 8 mol % of B 2 O 3 ,

e) from 0 mol % to about 8 mol % of ZrO 2 ,

f) from 0.01 mol % to about 1 mol % of P 2 O 5 , and

g) from 0 mol % to about 5 mol % of Na 2 O

having a major crystalline phase comprising from about 20% to about 80% of a β-spodumene phase and from about 20% to about 80% of a petalite phase and a minor crystalline phase comprising up to 10% of a lithium silicate crystalline phase;

wherein the lithium silicate crystalline phase comprises a lithium metasilicate crystalline phase; and wherein the composition exhibits density from about 2.00 g/cm 3 to about 2.6 g/cm 3 .

2 . The glass-ceramic composition of claim 1 , wherein the glass-ceramic composition exhibits an average transmittance greater than about 80% over a wavelength range from about 390 nm to about 700 nm as measured for a sample prepared from the composition and having a thickness of about 2.00 mm, wherein the glass-ceramic composition comprises a plurality of crystal grains having the median size of a crystal grain is from about 20 to about 80 nm; or

wherein the glass-ceramic composition exhibits an average transmittance between 20% and 80% over a wavelength range from about 390 nm to about 700 nm as measured for a sample prepared from the composition and having a thickness of about 2.00 mm, wherein the glass-ceramic composition comprises a plurality of crystal grains having the median size of a crystal grain is from greater than about 80 nm to about 500 nm; or

wherein the glass-ceramic composition exhibits an average transmittance lower than 20% over a wavelength range from about 390 nm to about 700 nm as measured for a sample prepared from the composition and having a thickness of about 2.00 mm, wherein the glass-ceramic composition comprises a plurality of crystal grains having the median size of a crystal grain is greater than about 500 nm.

3 . The glass-ceramic composition of claim 1 , exhibiting Vickers hardness equal to or greater than about 6.0 GPa, and/or exhibiting a crack-resistance greater than about 0.2 kgf, and/or exhibiting a thermal expansion coefficient from about 40×10 −7 to about 90×10 −7 /° C., and/or wherein the composition exhibits a glass transition temperature (T g ) from about 450° C. to about 600° C.

4 . The glass-ceramic composition of claim 1 , wherein the composition further comprises one or more of fining agents selected from CeO 2 , SnO 2 , Fe 2 O 3 , As 2 O 3 , Sb 2 O 3 , MnO 2 , or a combination thereof, and wherein the one or more fining agents are present in a total amount equal to or less than about 1 mol %; and/or further comprising one or more of coloring components selected from transition metal oxides and/or rare earth metal oxide, and wherein the one or more coloring components are present in a total amount equal to or less than about 1 mol %; and/or further comprising a decolorizing agent comprising sodium sulphate, selenium compounds, erbium oxide, cerium oxide, cobalt oxide, manganese oxide, or any combination thereof.

5 . A glass-ceramic article comprising:

the glass-ceramic composition of claim 1 , wherein the article comprises a hollowware, tableware, container, plate, sheet, float/flat sheet, cookware, powder, fiber, cones, spheres, blades, or any combination thereof.