Brucite, also known as hydrated magnesium hydroxide (Brucite) Mg(OH)2, boasts a modest hardness of 2.5 and a specific gravity ranging from 2.3 to 2.6. Its crystalline form often manifests as thick plates, commonly encountered as aggregations of platy structures; occasionally, it presents itself as fibrous aggregates, referred to as nemalite or brucite asbestos. Brucite typically forms in serpentinite or dolomite as a representative low-temperature hydrothermal alteration mineral.
The predominant coloration of brucite tends toward white to pale green, while specimens containing manganese or iron exhibit hues of reddish-brown. The color variation in brucite hinges upon the concentration of impurities such as iron or manganese; variants enriched with these elements may display shades of yellow or reddish-brown.
Brucite frequently finds application in ornamental crafts like bracelets and tea sets, emerging as a novel substitute for white jade. Artifacts fashioned from this material exhibit a predominantly white hue tinged with subtle green undertones. They possess a glossy sheen, occasionally accentuated by a waxy luster.
The ore appearance of brucite strikingly resembles that of Hetian jade, with fine fibers exhibiting transparency and a jade-like texture. Moreover, its exterior may even mimic the distinctive feature of Hetian jade ore – the white crust, rendering it remarkably deceptive. Such ores commonly appear in the vicinity of local jade deposits in Hetian region. Notably, carved ornaments and jade bracelets crafted from this ore have already surfaced in the jade market.
Distinguishing between Hetian white jade and brucite necessitates attention to three key aspects:
1. Observation with the naked eye reveals the intricate cloud-like patterns, known as “yunhua,” unique to Hetian white jade. The luster of Hetian white jade is gentle and subdued, unlike the intense glassy luster. In other words, the surface of Hetian white jade does not reflect light strongly due to the presence of very fine irregularities, akin to the surface of frosted glass, visible under a magnification of 10 to 20 times.
Pay attention to the incised lines. Despite the high hardness of Hetian white jade, it also possesses considerable toughness, making it resistant to chipping during carving. Therefore, there are generally no chips along the incised lines. Unlike other types of jade with high hardness but poor toughness and strong brittleness, incised lines are prone to chipping.
