"Chalchihuitls: Pre-Columbian Jade and Other Sacred Stones" -- at the new National Museum of Women in the Arts -- has to make one wonder. It just sits there like a lump, undigested, unexplained, hastily assembled. You think, why is this show here?

The National Museum of Women in the Arts claims a special mission. A fund-raising appeal from its executive director was mass-mailed last week: "Other museums have been devoted to neglected areas of art -- nationality, period, aesthetic movement. Isn't it about time you and I finally had the chance to see and appreciate history's most neglected body of art? ... The National Museum of Women in the Arts truly will be a stunning tribute to the lost women of history -- women artists ... So many lost women ... RSVP today!"

But then you see the jade show. You look into its cases. They're in no special order, their contents are mysterious, their labels tell you little. A catalogue would help, but this exhibit has no catalogue. Were these objects made by women? There is no way of telling. Do these green ax heads and pendants, these blood-letters and masks deal with the feminine? Not that one can see. And they were chosen by a man.

Then why is this show here?

It is here because the founder of the National Museum, Wilhelmina Holladay, runs her institution like a vanity museum.

She has mounted this exhibit as a favor for a friend.

The friend is Holland Hanson Coors. Perhaps because her husband Joseph Coors is a friend of the president's, and a generous supporter of his campaigns and his policies, Holland Coors has been appointed our ambassador to something called the "National Year of the Americas, 1987." She says, "I hope that this magnificent show, which demonstrates the complex imagery of jade objects created by pre-Columbian societies, will foster greater interest in learning more about our southern neighbors today." She comes from Colorado (as does Robert J. Stroessner, curator of New World art at the Denver Art Museum, who picked the things displayed). And she paid for the show.

It may well be the largest exhibition of Meso-American jades ever assembled. That's its one distinction. Despite the beauty of its objects (there are 162 of them) it is -- by the standards of Washington's museums -- a coarse and slipshod effort.

It opens with a curious quote silk-screened on the wall. The words are Montezuma's. He is addressing Herna'ndo Corte's. His words are taken from a volume of 1632, "The True History of the Conquest of New Spain."

"I will also give you some very valuable stones, which you will send to him {King Charles V} in my name. They are chalchihuitls and are not to be given to anyone else but him, your great prince. Each stone is worth two loads of gold."

Why were these stones so valuable? What functions did they serve? What gods did they evoke? Where were they found or quarried? How were they carved and smoothed? This exhibit does not deign to answer. Its objects sit there mute.

Seven of the strangest are in Case 2. Four of these are pointed things. They look like thick stone needles. The other three resemble spoons. The label says: "Votive and burial offerings often included ceremonial objects of fine stone. Some of these served functions which remain obscure today. Others allow us to speculate on both their ritual use and meaning. Here are two types of ritual objects from Olmec times: PERFORATORS (blood-letters) and SPOON PENDANTS."

What did those perforators perforate? Whose blood did they let? There are scholars who, citing Olmec documents, contend that Olmec males pierced their penises, and females their tongues, in ceremonial blood lettings in homage to their gods. Those spoon pendants may once have held sacred plants and mushrooms, or perhaps the dripping blood. But if curator Stroessner has opinions on such findings, he keeps them to himself.

We are told that green stone was highly valued by the Olmecs and the Mayas, the Incas and the Aztecs, because its "color was sacred -- symbolizing growth, regeneration and life." It is true that the green jades displayed suggest the look of growing things, and the bluish jades beside them look like water turned to stone. But if their colors made them sacred, what are we to think of stones of brown and beige and black?

One of the strangest aspects of this strange exhibition is the way it calls to mind ancient Oriental art.

The 3,000-year-old ax heads with which the show begins (some so precious they were later cut in two or quartered, as if split to spread the wealth) recall old jades from China. So, too, do the ear discs. And a marble vase displayed (circa A.D. 1000, it comes from the Ulna Valley of Honduras) looks like a close cousin of a Chinese bronze. Is this just coincidence? Or were there connections of some sort between, say, ancient Mexico and ancient China? The labels do not say.

Nor do they tell us much about those small stone hunchbacks, or those frowning masks, or those pea pods made of stone.

Museums ought to teach, or at least they ought to try to. The National Museum of Women in the Arts has more than 70,000 paying members. Do they care that their museum is mounting arbitrary shows or renting out its galleries to its founder's friends? The women's museum was roundly ridiculed when it opened here last April. One would think it had caught on. It has a long, long way to go.