周金云

在加利福尼亞州科林加的深山中，人們可以挖掘到地球上最稀有的寶石。

1 Deep in the hills of Coalinga， California， members of the public can dig for benitoite， the rarest gem （寶石） on Earth. The Benitoite Mining Company transports dirt directly from a hidden mine to an empty field on the site of what was once a prison.

2 Benitoite is made of a blue?colored crystal （水晶）. Under a shortwave ultraviolet （UV） light， the gem produces a bright blue to bluish white. That is the chief way collectors can identify （鑒別） it. The mineral can be visually identified by its glassy， blue color and double triangle （三角形） shape.

3 Visitors to the site are given a quart?size bag for the treasures they find throughout the day. “It paid off at the end of the day with some beautiful rocks and small gems，” said Keri Bean， a rock enthusiast from Pasadena.

4 James M. Couch discovered benitoite more than a century ago， in 1906. He thought he had found sapphires （藍寶石）. However， John Schreiner， the co?owner of the Benitoite Mining Company， explained that the discovery was actually “a new gemstone that had never been found before”.

5 “Many people who come to dig know very little about the gemstone，” Schreiner said. The company employs （雇用） a small team of workers who mine during the week. The gems they find are cut and sold for jewelry. Benitoite is currently valued at about $4，000 per carat （克拉）.

6 Every Saturday， from 9 am to 3 pm， visitors are welcomed to enjoy a mining experience. Upon arrival at the camp， visitors are greeted by a staff member who conducts a brief tour of the historic prison. At the piles of dirt， visitors are shown how to dig， wash， and identify gems. “The hardest part was sifting （篩分） the rocks out of the dirt，” Bean said. After the rocks are thoroughly cleaned in three washbins， they are ready for sorting. Two rooms are set up with shortwave UV light stations， and the screen of clean materials is placed under the light. The rocks that glow （發(fā)光） are benitoite.

1. How can collectors identify benitoite？

A. By asking the public for help. B. By using a special light.

C. By matching triangle things to the gem. D. By looking for green colors in the gem.

2. Which word can describe the experience of finding gems according to Keri Bean？

A. Worthwhile. B. Meaningless. C. Silly. D. Changeable.

3. Who discovered benitoite first？

A. A rock lover from Pasadena. B. James M. Couch.

C. John Schreiner. D. A worker from a mining company.

4. What do visitors do first at the camp？

A. Search for gems. B. Learn something about gems.

C. Tour around the historic prison. D. Clean the dirt on the rocks.

Useful expressions

dig for 挖掘

the rarest gem 最稀有的寶石

transport sth from...to 把某物從……運輸?shù)健?/p>

a blue?colored crystal 藍色水晶

pay off 得到回報

upon arrival at 一到達……就……