johachidolite — species of mineral; see johachidolite in ‘Classification’ …
keystone — rare shape in faceting a gemstone …
kimberlite — an igneous rock; best known for sometimes containing diamonds …
kite — rare shape in faceting a gemstone …
kornerupine — species of mineral; see kornerupine in ‘Classification’ …
kunzite — variety of spodumene; see kunzite in ‘Classification’ …
kyanite — species of mineral; see kyanite in ‘Classification’ …
labradorite — variety of anorthite; see labradorite in ‘Classification’ …
lamproite — an igneous rock; sometimes contains diamonds …
lapis lazuli — a rock; see lapis lazuli in ‘Classification’ …
larimar — variety of pectolite; see larimar in ‘Classification’ …
lava — molten rock expelled by a volcano during an eruption …
lazulite — species of mineral; see lazulite in ‘Classification’ …
lazurite — variety of haüyne; data; constituent of lapis lazuli; see lazurite in ‘Classification’ …
leucite — species of mineral; see leucite in ‘Classification’ …
limestone — a sedimentary rock composed largely of the minerals calcite and aragonite …
linarite — species of mineral; data; faceted specimens exist; soft …
lizardite — species of mineral; see lizardite in ‘Classification’ …
londonite — species of mineral; data; faceted specimens exist …
lozenge — a shape in faceting a gemstone …
