"He's been on the radar ever since," Lucas said. "He's the real deal."
Now 6-10 and 250 pounds, Stone announced Friday that he would play at Maryland, choosing the Terps over home-state Wisconsin as well as defending NCAA champion Connecticut and Oklahoma State. His decision took his parents and Maryland coach Mark Turgeon a little by surprise, coming less than an hour after Turgeon and assistant coach Bino Ranson, who had recruited him since the ninth grade, had finished an in-home visit.
On Wednesday night at Chicago's United Center, Stone will join Melo Trimble as the second Terps commit to play in the McDonald's All American Game in as many years; the program's last such player, Mike Jones, arrived in College Park in 2003.
Unlike former Terp Shaquille Cleare, ESPN.com's sixth-rated center and No. 30 overall player in the Class of 2012, Stone gets by more on basketball savvy than brute strength.
DeShawn Curtis, a former Division II player who has trained Stone since he was in the third grade, said Robert Stone had a simple goal in mind when he brought his then-9-year-old son for their first session.
"He wanted him to be a post player. There was no give-and-take with that; understanding every nuance of playing around the basket was imperative to his development," recalled Curtis, later the coach of Stone's Amateur Athletic Union team, the Young Legends.
Robert Stone, a two-time All-American at Division II Wisconsin-Whitewater in the mid-1970s, had a role model in mind when he started teaching his son the game.
"Our goal was to have him be solid 18 [feet] and in, more like a Tim Duncan," he said. "Go inside and outside. He just took to it. I guess you would call him a 'stretch 4 or 5' now. You have to evolve."
A star is born
Diamond Stone said Sunday that those early training sessions with Curtis marked the start of his development into one of the nation's top players.
"I just wanted to get better," Stone said in Chicago. "I'd see other kids around me, you know, doing stuff I couldn't do because I wasn't capable of doing it. I wanted to be able to do those things."
It was a slow process, according to Curtis. He took a kid who was oversized and overweight — "He was huge; he was always huge," Curtis said — and taught him the simple things: how to catch the ball, pivot and pass.
Each year, Stone added another dimension, becoming more skilled and more confident. Curtis eventually gave up traveling overseas to train teams in China and Spain so that he could work more extensively with Stone.
"I knew he had something special, and I wanted to see how far he could go," Curtis said.
By the time Stone arrived in Houston for Lucas' camp, the first five years of work paid off.
"It was pretty spontaneous," he said. "But a diamond is the strongest substance."
By the end of his freshman year at Dominican High, a private, Catholic school just north of Milwaukee, the younger Stone was being mentioned among the top high school centers for his age.
In the state championship game that year — which ended with the first of four straight titles for the Knights — Stone had a triple double: 15 points, 15 rebounds and a state-playoff-record 14 blocked shots.
As Stone became the focal point of opposing defenses — typically tightly packed zones that would collapse on the biggest player on the court — his perimeter game developed.
Robert Stone said his son's ranking fell as a result, from the top center in the country to the second- or third-best. Once widely rated as among the top two or three players nationally, Stone is now in less elite company: He's in the top 10.
"He's paid the price for it nationally," his father said recently. "The people doing the rankings say that he's not a true post player, so we can't treat him that way. They say he's a stretch guy.
"Who cares about that? We tried to grow a basketball player, tried to develop a basketball player. He does a lot of things well. As you can see, he's not just a post player. He's a leader. He shoots good free throws for a big man."
In a state sectional semifinal last month, a 55-51 win over St. Catherine's High played at Milwaukee South High, Stone got off to a fast start. But a 2-3 zone defense bottled him up for much of the second and third quarters.
In the fourth quarter, Stone stepped outside the arc to hit two of his four 3-pointers, found a teammate for a backdoor lob dunk, then hit four straight free throws in the final 30 seconds to seal the victory. Stone, who averaged 24.6 points and 11.9 rebounds per game as a senior, finished with 31 and 11, respectively.
"Diamond tends to do whatever needs to be done for us to win," Dominican coach Derek Berger told the Milwaukee Journal Sentinel after the game.
'All Eyes On Me'
Don Showalter, who coached Stone the past two summers on USA Basketball's under-16 and under-17 teams, compares Stone to another former national-team player.
"I've said this for quite a while: He's a lot like Jahlil Okafor," Showalter said. "Both of them have great footwork around the basket, use their right and left hand. Jahlil is a little more physical, a little more aggressive. … Diamond's a little better on the perimeter."
Showalter said Stone still has plenty of room for growth and thinks Maryland's inside-out offensive system is a great fit.
"He has just tapped the surface, in my opinion," Showalter said. "He hasn't figured it out, how hard he has to play. Like any good player, those guys are so good, they can take plays off, and it doesn't make any difference. When they figure it out at the next level, 'Hey, I can't take any play off,' that's when they progress."
Showalter said he saw a difference in Stone when he returned last summer in much better shape. Showalter said Stone had "transformed" his body, particularly his core.
"That showed me how hard he worked, and where he wants to go," he said of Stone, who will try out for the under-19 team coached by Florida's Billy Donovan that will compete in Greece's FIBA World Championship this summer.
There are some who wonder whether Stone will be Turgeon's first one-and-done at Maryland. Stone already is being mentioned as a lottery pick in the 2016 NBA draft, as high as No. 5 overall, where the Phoenix Suns selected former Terps center Alex Len in 2013.
Curtis has not heard any talk of how long Stone plans to stay at Maryland, though he knows it might not be long.
There's "not a lot of talk in his camp [about] making sure he's a one-and-done," Curtis said. "His parents are really concerned with him growing up and maturing as a young man, getting educated and all that good stuff. But if the opportunity presents itself, he'd have to analyze and really weigh your options. The goal really is to maximize his potential while he's there."
Stone told the Glenn Clark Radio Show on Monday that he had to turn off his Twitter notifications once he chose Maryland. Many Badgers fans questioned whether he would have qualified academically for Wisconsin — a claim he has since rebutted, saying he had gotten the requisite score on his latest ACT.
Robert Stone said the negative response only showed why his son, whose Twitter profile includes the words "All Eyes On Me," might have felt the need to get out of Wisconsin.
"A lot of guys like to get away from home," Stone told reporters in Chicago on Tuesday. "It's part of experiencing life — being independent and seeing what's out there."
In accordance with NCAA rules, Turgeon is not allowed to comment publicly on Stone until he signs his scholarship agreement or financial-aid forms.
Robert Stone said his son isn't caught up in the hype that has followed him the past few years, hype that will accompany him to College Park when he arrives this summer for his first team workout.
"In his eyes, he hasn't gotten there yet," Robert Stone said. "He's still on the journey."