. . AMBKK. MALACHITE, LAl^IS-LAZULI AND AZURITE. ». Iv A. w llulfmo, OHKAM. Lapis-lazuli, poIi8lieolislied. showiiiR insicts enclosed (Coast of Riltic Sea) Amber, rolled pebble (Coast of Baltic Sea). Malacbite. polished (Tral Mountains). :i .. LOANED BY FOOTE I AmazoMstone, crystallized (Colorado). Lalirudorite. iMilislicil (). Siiii-tiiH (Noiwav). , crvstallized (Colorado). Aniazonstone (Colorado). Labradorite, (Labrador). Moonstone, polished (Norway), PRECIOUS STONES 51 its
. . AMBKK. MALACHITE, LAl^IS-LAZULI AND AZURITE. ». Iv A. w llulfmo, OHKAM. Lapis-lazuli, poIi8lieolislied. showiiiR insicts enclosed (Coast of Riltic Sea) Amber, rolled pebble (Coast of Baltic Sea). Malacbite. polished (Tral Mountains). :i .. LOANED BY FOOTE I AmazoMstone, crystallized (Colorado). Lalirudorite. iMilislicil (). Siiii-tiiH (Noiwav). , crvstallized (Colorado). Aniazonstone (Colorado). Labradorite, (Labrador). Moonstone, polished (Norway), PRECIOUS STONES 51 its ores oxidize in the air. Many of the green stains onrocks or minerals can be correctly referred to malachite. Itis only valued for ornamental purposes, however, when itoccurs in compact masses, usually exhibiting concentriclayers. Malachite in this form takes a fine polish. Mala-chite is not a hard mineral, its hardness being between 4. FELDSPAR Feldspar is the family name of several minerals closelyrelated, and, indeed, grading into each other, but distin-guished by mineralogists by separate specific terms. Theseminerals are all silicates of aluminum, with some alkali oralkali earth, having a hardness of about 6 in the scale inwhich quartz is 7. As ornamental stones only certain varieties of feldsparare
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectnaturalhistory, booky
