pleochroism

Pleochroism: distinct in strong colored gem varieties, kunzite is violet-purple/colorless and hiddenite is green to blue-green/colorless to pale green.

体多样：不同的锂辉石具有明显的强烈颜，锂辉石具有罗兰到或者无，希登石是绿到蓝绿或者无到淡绿；

When cutting most pleochroic gemstones (Iolite, Tanzanite, Kunzite etc.), lapidaries typically try to minimize the pleochroism and maximize the single most prominent color.

在切割大多数的多向宝石时（如堇青石、坦桑宝石、锂辉石等），通常宝石匠会尽量缩小多向并最大化地将某一主凸显出来。

(3) the observations and determination methods of form, cleavage, Becke line, shagreen surface, relief, pseudo-absorption, absorption, color, pleochroism of minerals under plane polarized light;

⑶单偏光镜下矿物的形态、解理、多、吸收、糙面、突起、贝克线等观察与测定方法；