CNBC's Jim Cramer on Wednesday deciphered between what he sees as speculative and blue-chip stocks in a market that's shaped by the coronavirus pandemic.

"The whole market's being upended by the pandemic and the lines they are shifting," the "Mad Money" host said. "Formerly rock-solid companies are now on dangerous footing. Formerly speculative outfits have become titans of emerging industries."

After daily new Covid-19 cases topped 40,000 on Tuesday and more states placed restrictions on business activity, the S&P 500 and Nasdaq Composite both rose less than 1% in Wednesday's session. The Dow Jones Industrial Average was the outlier, slipping almost 78 points, or 0.30%, to 25,734.97 on the first trading day of the third quarter.

"This is a terrible situation for our country, it's really bad for the economy as a whole, but incredibly that doesn't necessarily mean it's bad for the stock market," Cramer said. "Think of the stock market like a casino for a moment... When Covid cases spike, people don't cash in their chips and go home, do they? No, they go where the action is. They go where the hot tables are, the hot slots, the hot wheels."

Stocks were lifted in part by new positive information about a coronavirus vaccine being developed by Pfizer and BioNTech. The data indicated its capability to produce neutralizing antibodies, though the study has yet to be peer reviewed. Pfizer shares rallied 3% during the trading day.

Among Wednesday's winners, Cramer pointed out FedEx shares, which popped 12% on a strong quarterly report driven by shipping demand in the stay-at-home economy.

"If we can get a vaccine sooner than expected, that's huge for vast swathes of the economy, although it's terrible for the smaller vaccine plays, which is why they got eviscerated," the host said.

"FedEx and Pfizer are blue chips that spurred all sorts of high-flying stocks to become even more expensive, and with good reason," he added.

FedEx's ripples could be seen in investors buying e-commerce plays like Amazon, Shopify, Etsy, Adobe, Wix.com, Fastly and Salesforce, Cramer said.

There are other "super-speculative names" that Cramer said are "classic Lotto stocks."

On that list includes: Workhorse, up 500% this year despite the utility vehicle manufacturer "losing a fortune," NIO, a Chinese car maker that's up nearly 100% this year, Tortoise Acquisition, which fell 8% Wednesday, VBI Vaccines and Vaxart, he said.

"There's a sane part of this market where high-quality stocks roar because they benefit from the stay-at-home economy. Think about all that FedEx pin action," Cramer said. "Then there's the crazy part of the market that's driven by rampant speculation, and that's a very different … likely ill-fated story."

Disclosure: Cramer's charitable trust owns shares of Salesforce and Amazon.