An Examination of Red Beryl

By FRANK MILEY Graduate Gemologist Los Alamos, New Mexico

Introduction sions. The largest faceted red beryl that has been reported 3 is 2.93 ct. Red beryl is a gem that has recently The author has not had the oppor- been coming into prominence. Where tunity to see or examine this rare does it come from? How much is gemstone. available? What does it look like? In some literature red beryl is listed How can it be identified? Recent as bixbite. If you should do a litera- acquisition of a faceted gem prompted ture survey, you should be aware of these questions. After researching both names. In this article it is re- available literature and finding very ferred to as red beryl. little gemological information, it be- came obvious that some personal re- Properties search was to be done on as much red Several faceted specimens of the beryl as could be examined. Utah material were examined for this report. New Mexico material was on Sources display- as crystal specimens; it was Red beryl is only found in three much too small to be faceted. This locations in the United States. No material was not available for micro- other sources have been reported. It scopic examination. It was noted occurs in the Thomas and Wah-Wah however, that the tone and hue were Mountain ranges in Utah I and in the very close to that of the Thomas Black Range in New Mexico 2. All Mountain material. The Utah mater- crystals are small; the largest crystals ial exhibited differences in transpar- are found in Utah. The Utah material ency, tone, hue, and intensity. They provides faceted gemstones that are are listed as "T" Thomas Mountains, generally less than .5 ct.; common and "W" Wah-Wah Mountains. The sizes usually range from .1 ct. to .4 ct. information obtained from examin- Nearly all faceted gems exhibit a high ing the Utah materials is listed as degree of internal fractures and inclu- follows:

WINTER 1980-1981 405 Description: "T" Translucent, dark orangy-red of medium intensity. "W" Semitransparent, medium red of high intensity, see Figure 1. Crystal character: Hexagonal. Fracture: Conchoidal. Specific gravity (al: 2.65 Characteristic inclusions (b) : Fingerprint pattern. Transparency: Semitransparent to translucent. Luster: Polish is vitreous. Fracture is vitreous. Refracti ve index (c) : 1.561(±.001) - 1.569(±.001) Birefringence: .008 Optic character (d) : Uniaxial. Pleochroism: Purplish-red and orangy-red. Ultraviolet fluorescence: Inert to both wavelengths. Color filter: No reaction. A bsorption spectra (e): No diagnostic spectra.

(a) The value of 2.65 was deter- fingerprint patterns, see Figure mined by using heavy liquids. 2. It also contains bizarre shaped The gemstone tested floated in a healing voids. Both of these types liquid of 2.67 specific gravity and of inclusions were in planes or sank in a liquid of 2.62 specific curved surfaces. There were more gravity. The heavy liquid method fingerprint patterns present than was used because there is a possi- the planes of healing voids. The bility for a great variation in fingerprint patterns in red beryl determining the specific gravity have been characteristic. At 20X, on small specimens. The exam- straight sided and round inclu- ined specimens were all small, sions were intermixed. At 60X, consequently, as a secondary the straight sided inclusions were method of determination, three pointed and the round 'inclusions faceted gems were used simultan- appeared to have short straight eously to determine the specific sides. At l25X, much smaller gravity by the immersion method. inclusions began to appear in The combined weight of the three between the inclusions described faceted gems was .52 ct., and the at 60X. specific gravity as determined by When magnified, all faceted this method was 2.67. The pub- gemstones had one or more in-

lished value 5 for red and violet ternal fractures that extended to beryl lists the specific gravity the girdle. range to be 2.77 to 2.87. No other inclusions were noted (b) Red beryl was highly included in all specimens examined up to with secondary inclusions con- l25X. sisting of single phase, gas filled, (c) A Duplex II Refractometer

406 GEMS & GEMOLOGY Figure 1. A 20 ct red beryl from Wah-Wah Figure 2. Fingerprint Inclusions at 36X. mountains dark field

wa~ used wit h ~1enoch r«rnru ic .1nalyzcr i.'I n I ..I small gll:l~s sphere Yellow LIght to determine the wa~ in contac \\ iI h 1 he ~P~C!- retracuve index 01 each gem- men .. Thi5 arra ngcmcnt showc I stone. lhe pubnshed VLilL1l:~ ior the g.en1~ tll bnve it sbarp uniaxial red a nd VIOI<:l beryl lists the Interference iigur e. refractsve index range at I 585 I he pul lished va luc ! Ior heryl I:t.006) - 1.594 r . mr~l SI nee is umaxial neg •rtrve. there was n difference between (C) r he nu ruberb S Spectroscope published am.! experimemal data. tI lit was used w cheek the gem- high and low uandurds were ~tllne" for the speer roscopic a nal- used to check the instrument. ysls. -:\0 diagnosuc data was oh- The reading ibtained [ut sap- tained from the usc nl this instru- phire was 1.762 1.770 und the rncnt. The red color was reported J reading or quartz was I. 44. 1l~be caused from the presence of A ienes of readrn g~ were Ib- rnangancso I 1n'~, this has been tained hy rotaung euch gemstonr determined bv microprobe' a nul- on the hemisphere ol the refrnc- ysis. The absorption vpcctra I~S[s romerer. Rc d ings were nht:li nco perfm mcd on the red berv Ispcci- at 0, 45. 90, and 1;1) degree mens that wcr examined did no1 positions and each was plotted ind icute any tliagnc:;li' ab orpti. n. on a chart This 'N<.H done 10 determine I he bl refnngc ace. Photographs (d) l'he uniaxial rruerfercnce rig- Figur« t IS a photogra ph of

WJNTER 1980-1981 407 Conclusion References If faceting grade red beryl becomes (I) Ream, Lanny R., The Mineralogical more plentiful it should become a Record, P. 261, October 1979, The Thomas Range, Wah-Wah Moun- popular gemstone. The red hue of the tains And Vicinity, Western Utah. Wah- Wah Mountain material resem- (2) Kimbler, Frank S. and Haynes, Pa- bles ruby and ruby red spinel. The red trick E., New Mexico Geology. P. 15, hue of the Thomas Mountain and February, 1980, An Occurrence Of Black Range material is slightly darker Red Beryl In The Black Range, New and resembles cuprite. Red beryl is Mexico. " (3) Barlow, F. John, Lapidary Journal, highly included and contains internal P. 2540, 1979, Red Beryl Of The fractures, consequently, the durabil- Wah-Wahs. ity should be comparable to highly (4) New Mexico Minerals Symposium, included emerald and should be used UNM Campus, Albuquerque, N.M., in protective type mountings. September 29, 1979. (5) Gem Identification Course of the Gemological Institute of America.

408 GEMS & GEMOLOGY